Method of coating film, coating unit, aging unit, solvent replacement unit, and apparatus for coating film

ABSTRACT

Prior to transfer of an wafer W, a mixed gas is being generated and exhausted, thereby fluctuation of concentration and temperature of a solvent component at the beginning of gas introduction into a chamber  3  is suppressed. A step of gelling after the wafer W is carried into an aging unit is divided into several steps. Until a temperature of the wafer W reaches a predetermined treatment temperature, an average concentration of the solvent component in a mixed gas is gradually raised relative to the temperature of the wafer W. Thereby, immediately after the wafer W is transferred into a sealed chamber, the gas of the solvent component is prevented from condensing.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a coating method of forming aninsulating film by coating a coating liquid dispersed therein particlesor colloids destined to be a starting material of a film component in asolvent on a surface of a substrate, and relates to a coating unit, anaging unit, and a solvent replacement unit, and a film coating apparatusfor coating a film.

[0003] 2. Description of the Related Art

[0004] As a method of forming an interlayer insulating film of asemiconductor device, CVD and thermal oxidation are well known. On theother hand, other than these, there is a method called a sol-gel method.In this sol-gel method, a coating liquid dispersed colloids of TEOS(tetra-ethoxysilane; (Si(C₂H₅O)₄) in an organic solvent such as ethanolsolution is coated on a surface of a semiconductor wafer(hereinafter,simply refers to as wafer), the coated film, after being gelled, isdried, to obtain a silicon oxide film. The examples of this sol-gelmethod are disclosed in Japanese Patent Laid-Open Application Nos.HEI-8-162450 and HEI-8-59362.

[0005] Behavior in the course of change of the coated film in thissol-gel method is shown schematically in FIG. 10A through FIG. 10C.First, particles or colloids 100 of the TEOS, when coated on a wafer,are in a dispersed state in a solvent 200 (FIG. 10A). Then, this coatedfilm, by being subjected to an basic atmosphere or to heating, ispromoted in polycondensation and hydrolysis of the TEOS. As the result,the coated film is gelled to form a reticular structure of the TEOS300(FIG. 10B).

[0006] Next, in order to remove moisture in the coating liquid, thesolvent in the coated film is replaced by another solvent 400 of whichboiling point is low and surface tension is small(FIG. 10C). By dryingfurther thereafter, a coated film of a silicon oxide film is obtained.

[0007] Incidentally, a step of replacing the solvent shown in FIG. 10Cis carried out to remove moisture. Further, the step of replacing withthe solvent is carried out with an object to make the film hydrophobic.That is, since OH group is liable to absorb the moisture, the OH groupcombined to a terminal portion of Si—O bond is replaced by anotherorganic substance by cleaning the film with, for instance, HMDS or thelike.

[0008] Further, another object is to suppress collapse of a structure ofthe film by employing a solvent of smaller surface tension than ethanolso that a large force is not placed on the reticular structure of theTEOS when the solvent vaporizes.

[0009] Thus, there are an uncountable number of minute pores in thesilicon oxide film formed by the sol-gel method, there comes in air.Therefore, relative dielectric constant of the oxide film ε is close tothat of air. Therefore, the electric resistance of the oxide filmincluding such minute pores becomes such high as is close to that ofair, resulting in an ideal insulating film.

[0010] In order to apply such a sol-gel method in an actualmanufacturing line, a coating unit of coating a coating liquid on awafer, an aging unit of gelling the coated film by heating the wafer ata pre-determined temperature, for instance, at 100° C., and areplacement unit of replacing the solvent in the coated film by anothersolvent are necessary. Further, a pre-treatment unit for carrying outthe pretreatment such as hydrophobic treatment to the wafer, and abaking unit of drying the wafer are also necessary. And, by disposing atransfer mechanism of transferring the wafers between respective units,an apparatus is constituted.

[0011] Now, upon carrying out gelling treatment of the coated film, itis necessary that, through suppression of evaporation of the solventfrom the coated film, gelling of the TEOS is made not to be disturbed.For this, it is not desirable to carry out gelling operation in an opensystem like the conventional method. Instead, the gelling treatmentneeds only to be carried out in a sealed container of an atmospherefilled with vapor of the solvent. That is, after disposing a wafer on astage heated at a pre-determined temperature in the sealed container,gas including vapor of the solvent needs only to be introduced.

[0012] Now, the inventors of the present invention investigated to carryout the gelling operation with an aging unit 3 of a structureillustrated in FIG. 11, for instance. The aging unit 3 comprises aheating plate 30, a cover 33 provided with a heater, a gas introducingpath 34, and a gas exhausting path 35.

[0013] As shown in FIG. 11, in this aging unit 3, the heating plate 30is formed of ceramic and incorporates a heater 31 a.

[0014] The cover 33 is provided with a heater. This cover 33 isintimately connected to a circumference portion of the heating plate 30through a sealing member 32, and, together with the heating plate 30,constitutes a sealed container defining a treatment chamber S.

[0015] In the heating plate 30, outside along the circumference portionof the wafer W, a gas introducing inlet 34 a is formed in slit. This gasintroducing inlet 34 a penetrates the heating plate 30 and is connectedto a gas introducing path 34 introducing gas from the outsides.

[0016] At the central portion of the cover 33, an exhausting outlet 35 ais disposed. This exhausting outlet 35 a penetrates the cover 33 toconnect the exhausting path 35 communicating with the outsides. Inaddition, to the aging unit 3, 3 pieces of pins 36 for going up and downare disposed, for instance, and with these pins for going up and down,the wafer W is moved up and down between the heating plate 30 and theabove position thereof.

[0017] As a gas to be employed here, a gas of a solvent component, forinstance, vapor of ethylene glycol, is employed in order to suppressevaporation of the solvent inside the coated film during the atmospherefor heat treatment is heated.

[0018] And the gas introducing path 34 is disposed penetrating theheating plate 30. Therefore, the gas is introduced into the sealedcontainer after being heated to approximately 100° C., for instance, ora temperature extremely close to that temperature. At this time, theconcentration of the vapor of ethylene glycol is a concentration that isequal with the saturated vapor pressure at a treatment temperature ofapproximately 100° C., for instance. Further, in addition to ethyleneglycol, a gas accelerating gelation, ammonia gas, for instance, can beintroduced simultaneously.

[0019] However, in such a sealed container as the aging unit 3 shown inFIG. 11, when introduction of gas therein is started, there is such aproblem that until supply of the gas reaches a steady state, theconcentration and temperature of the gas fluctuate.

[0020] Also as aforementioned, in the case of a wafer being processed ata pre-determined temperature higher than normal temperature, 100° C.,for instance, when the wafer of the room temperature is transferred asit is into the sealed container of a pre-determined temperature, the gasof the solvent component which is at the saturated vapor pressure in thesealed container contacts with the wafer, to lower the temperaturethereof. As the result, it becomes a supersaturated state, and the gasof the solvent component is likely to condense. When ethylene glycol,for instance, condenses on the wafer, the thickness of that part becomesthick, resulting in a problem of becoming a non-homogeneous insulatingfilm.

SUMMARY OF THE INVENTION

[0021] The first invention of the present application is made to solvesuch a problem.

[0022] That is, an object of the first invention is to provide a methodof coating a film which are capable of suppressing fluctuation oftemperature and concentration at the starting time of gas introductioninto a sealed container, capable of preventing the solvent componentfrom condensation immediate after transfer of a substrate, for instance,an wafer into the sealed container, and capable of obtaining thereby athin film, for instance, an interlayer insulating film, of an excellentquality, an aging unit, and an apparatus of coating a film.

[0023] For this, a method of coating a film of the first inventioncomprises the following steps as disclosed in claim 1:

[0024] a step of forming a film by coating a liquid, in which particlesor colloids of a starting material of a film component is dispersed in asolvent, on a surface of a substrate;

[0025] a first gelling step of, in addition to transferring of thesubstrate into a sealed container, gelling the substrate in a state ofthe coated substrate being exposed to gas including vapor of the solventof the coating liquid at a first average concentration; and

[0026] a second gelling step of gelling in a state where the insides ofthe sealed container is filled by a gas including the vapor of thesolvent of the coating liquid at a second average concentration higherthan the first average concentration.

[0027] Further, an aging unit for carrying out this method of formingthe film comprises:

[0028] a treatment chamber accommodating a substrate thereon a filmincluding a solvent and particles or colloids of starting material of afilm component is formed;

[0029] a heater of heating the substrate;

[0030] a carrier gas feeding system feeding the carrier gas towards thetreatment chamber;

[0031] a solvent dispensing system of dispensing the solvent towards thetreatment chamber;

[0032] a mixing system forming a gas mixture containing vapor of thesolvent from the carrier gas feeding system and the solvent dispensingsystem; and

[0033] an adjusting mechanism for adjusting concentration of the solventin the gas mixture.

[0034] Further, an apparatus of forming a film for carrying out theaforementioned method of forming the film comprises:

[0035] a coating unit of coating a liquid in which particles or colloidsof a starting material of a film component is dispersed on a surface ofa substrate;

[0036] an aging unit comprising a treatment chamber accommodating asubstrate thereon a film is formed, a heater heating the substrate, acarrier gas feeding system feeding a carrier gas towards the treatmentchamber, a solvent dispensing system dispensing the solvent towards thetreatment chamber, a mixing system forming a gas mixture containingvapor of solvent from the carrier gas feeding system and the solventdispensing system, an adjustment mechanism adjusting concentration ofthe solvent of the gas mixture, and

[0037] a solvent replacement unit replacing the solvent in the coatedfilm.

[0038] In the aforementioned method, the gas introduced into the sealedcontainer in the first gelling step is preferable to be adjusted intemperature to approximately a temperature of the inside of the sealedcontainer.

[0039] According to the first invention, after a substrate istransferred into a sealed container until the temperature of thesubstrate reaches the pre-determined temperature, the averageconcentration of the solvent component is made low. On the other hand,when the temperature of the substrate becomes high, the concentration ofthe solvent component is made high. Therefore, immediate after thesubstrate is transferred into the sealed container, the gas of thesolvent component can be prevented from condensation.

[0040] Incidentally, before transferring the substrate into the sealedcontainer, it is preferable that while a mixture of vapor of the solventcomponent and a carrier gas is formed, the gas mixture is beingexhausted. By implementing like this, the fluctuation of theconcentration of the solvent component and the temperature can besuppressed at the starting of gas introduction.

[0041] Specific examples of the first invention are cited as follows. Astep of gelling particles or colloids of the coated film is one thatheats the substrate. Further, the gas to be introduced into the sealedcontainer is made by mixing a carrier gas and the vapor of the solventcomponent. The first gelling step is carried out by adjusting the flowrate of at least one of the carrier gas or the vapor of the solventcomponent. Further, mixing of the carrier gas and the vapor of thesolvent component is carried out at an evaporator which evaporatesliquid of the solvent component. The first gelling step is carried outby adjusting the flow rate of the liquid of the solvent component beingintroduced into the evaporator.

[0042] In this case, the first gelling step includes the step of varyingcontinuously the concentration of the vapor of the solvent component.Further, the first gelling step includes the step of mixingintermittently the vapor of the solvent component with the carrier gas.

[0043] Further, the second gelling step includes the step of, after thefirst gelling step is carried out subsequent transfer of the substrateinto the sealed container, feeding the gas into the sealed container ina state where the average concentration of the vapor of the solventcomponent is higher than that during the first gelling step.

[0044] Further, an average concentration of the solvent of the gas beingexposed to the substrate at each step is preferable to be theconcentration corresponding to the saturated vapor pressure at thesubstrate temperature at each step. For instance, the aforementionedfirst average concentration is preferable to be the concentrationcorresponding to the saturated vapor pressure at the substratetemperature at the time of introduction of the container, the secondaverage concentration being preferable to be the concentrationcorresponding to the saturated vapor pressure at the substratetemperature during gelling.

[0045] The reason is that there is a problem that, when the averageconcentration of the solvent in the gas is lower than the saturatedvapor pressure, the solvent volatilizes from the coated film on thesubstrate, resulting in difficulty of generating pores in the film.

[0046] On the other hand, when the average concentration of the solventin the gas is higher than the saturated vapor pressure, there is aproblem that the vapor condenses on the substrate or on the wall of thetreatment chamber, the condensation on the substrate inducesdeterioration of the film quality, and the condensation on the wall ofthe treatment chamber tends to cause contamination of the apparatus orre-sticking on the substrate.

[0047] Next, as the second invention, the inventors investigated to forman interlayer insulating film by use of sol-gel method illustrated inFIG. 10A to FIG. 10C.

[0048] Here, the inventors further attempted to replace the solvent inthe coated film by another solvent 400 (FIG. 10C). In this replacementstep of the solvent, after replacement of water in the coated film byethanol, for instance, HMDS(hexamethyl disilane) is supplied to removeOH group, and finally replacement by heptane is carried out.

[0049] The reason for employing heptane here is to suppress collapse ofthe film structure by avoiding, with use of a solvent of low surfacetension, a large power placed on a reticular structure of TEOS duringvaporization of the solvent.

[0050] When applying such a sol-gel method into an actual manufacturingline, a coating unit for coating a coating liquid on a wafer, a gellingunit for gelling the coated film and a replacement unit for replacingthe solvent in the coated film by another solvent are necessary.

[0051] In the replacement step of the solvent, because of use of 3solvents as aforementioned, the present inventors attempted to employ aconventional resist coating device for the replacement unit.

[0052] The resist coating device will be described with reference toFIG. 18.

[0053] The device comprises a vacuum chuck 194 which is capable of goingup and down and rotates a wafer while holding in a horizontal position,a fixed cup 195, and a nozzle 196 for dispensing a solvent to the wafer.The fixed cup 195 is disposed such that it surrounds the wafer W on thechuck 194, and an opening portion at an upper surface is opened orclosed by the cup 195 a.

[0054] As the nozzle 196, 3 pieces of nozzles 196 a to 196 c whichdischarge ethanol, HMDS and heptane, respectively, are disposed. Thesenozzles of 196 a to 196 c are taken out in this order by grasping by acarrying arm 197 from nozzle receiving portions 198 a to 198 c, and aretransferred up to around the central portion above the wafer W.

[0055] In the case of carrying out the solvent replacement step of thesol-gel method with such an apparatus, first, in a state where the cover195 a is open, the wafer W is transferred to the chuck 194. Then,ethanol is dripped from the nozzle 196 a onto the wafer W, thereafterthe fixed cup 195 is closed, the wafer W is rotated. Thus, the ethanolis diffused over the whole front surface of the wafer W throughcentrifugal force. Thereafter, the cover 195 a is opened, similarly HMDSis supplied on the surface of the wafer W with the nozzle 196 b. Then,heptane is further supplied on the surface of the wafer W through thenozzle 196 c, to carry out treatment.

[0056] However, in the aforementioned apparatus, since 3 pieces ofnozzles 196 prepared for the respective solvents are grasped by acarrying arm 197 to transfer, when the solvent is supplied on thesurface of the wafer W, after transfer by the nozzle 196 a, the nozzle196 b is necessary to be transferred. That is, the carrying arm 197 wasrequired to repeat to go and return several times between the nozzlereceiving portion 198 and a position above the wafer W. Further, eachtime one solvent is diffused on the wafer W, the cover 195 a of thefixed cup 195 was necessary to be opened and closed.

[0057] Thus, the next solvent is impossible to be supplied continuouslysucceeding the supply of one solvent, supply of the solvent is stoppedto cause idle time.

[0058] Moreover, since until next supply of the solvent, a travellingtime of the carrying arm 197 and an opening/closing time of the cover195 a are piled up, a certain degree of time is necessary.

[0059] When it takes time between replacements of the solvents and thereis an idle time of the supply of the solvent, the solvent on the surfaceof the wafer, for instance, contacts with the air. Therefore, thereoccurs such an inconvenience as that moisture in the air is confined inthe film. And, as the result, the formed interlayer insulating film isdeteriorated in its film quality.

[0060] The second invention of the present application was made to solvesuch a problem.

[0061] That is, an object of the second invention of the presentapplication is to provide, in a method of forming a film having a stepof carrying out replacement of solvents by dispensing successively atleast a plurality of solvents on a surface of a substrate thereon acoated film is to be formed, a method of forming a film, a solventreplacement unit, and an apparatus for forming a film in which apreceding solvent and a succeeding solvent can be supplied continuously,thereby enabling to obtain an excellent thin film such as an interlayerinsulating film.

[0062] Therefore, a method of forming a film of the second inventioncomprises the following steps disclosed in claim 13:

[0063] a step of forming a film on a surface of a substrate by coating acoating liquid in which particles or colloids of a starting material ofa film component are dispersed in a solvent;

[0064] a step of gelling the particles or the colloids in the coatedfilm; and

[0065] a step of dispensing at least 2 kinds of replacement solventsdifferent from the aforementioned solvent on the surface of thesubstrate by switching successively;

[0066] wherein the switching of the replacement solvent to be suppliedis carried out by starting dispensing of the succeeding solvent whiledispensing the preceding replacement solvent, and thereafter by stoppingsupply of the preceding replacement solvent.

[0067] Further, a solvent replacement unit for carrying out this methodof coating a film comprises:

[0068] a treatment vessel accommodating a substrate formed thereon afilm containing the solvent and particles or colloids of the startingmaterial of the film component;

[0069] a spin chuck holding the substrate disposed in the treatmentvessel;

[0070] a plurality of solvent supply systems dispensing solvents towardsthe substrate; and

[0071] a switching device for switching the plurality of solventdispensing systems.

[0072] Further, an apparatus of forming a film for carrying out theaforementioned method of forming a film comprises:

[0073] a coating unit forming a film on a surface of a substrate bycoating a liquid in which particles or colloids of the starting materialof the film component are dispersed in a solvent;

[0074] an aging unit for gelling the coated film; and

[0075] a solvent replacement unit consisting of a treatment vesselaccommodating a substrate formed thereon a film containing the solventand particles or colloids of the starting material of the filmcomponent, a spin chuck holding the substrate disposed in the treatmentvessel, a plurality of solvent supply systems dispensing solvents to thesubstrate, and a switching device switching the plurality of solventsupply systems.

[0076] In the method of the second invention, since the supply of thesucceeding solvent begins before the supply of the preceding solvent isceased, the preceding solvent and the succeeding solvent arecontinuously supplied on the surface of the coated film without beinginterrupted. Thus, in the solvent replacement step, there is no time ofinterruption of supply of the solvent on the surface of the substratethereon the coated film is formed. Therefore, occurrence of such aninconvenience as that occurs due to stoppage of the supply of thesolvent, inclusion of moisture in the coated film, for instance, can besuppressed, resulting in formation of an excellent thin film on thesubstrate.

[0077] In the second invention, in the solvent replacement step, amongthe plurality kinds of solvents, at least 2 kinds of solvents may besupplied on a substrate from a common solvent dispensing portion, eachof the plurality of kinds of solvents may be supplied on the substratefrom separate solvent dispensing portions. Further, in the solventreplacement step, alcohol, a liquid for hydrophobic treatment, and asolvent of smaller surface tension than the solvent contained in thecoating liquid, for instance, are supplied in this order on thesubstrate.

[0078] Next, as the third invention, the inventors attempted to use spincoating, which is used in coating of resist, as a coating method. Inthis unit, on the central portion of the wafer sucked to a spin chuck,the coating liquid is dripped, the spin chuck is rotated to thin out thecoated film over the whole surface through centrifugal force to coat.

[0079] Now, since, during coating of a coating liquid, the wafer isrotated with high speed, air flow is generated along the surface of thewafer, resulting in speedy evaporation of the solvent in the coatingliquid. Therefore, evaporation of the solvent is being tried to besuppressed by adjusting the temperature and humidity of the coating unitand the temperature of the coating liquid. However, it is difficult tosuppress sufficiently the evaporation of the solvent through onlyadjustment of their temperature and humidity. In addition, when thesolvent evaporates much, gelling of the solvent is disturbed todeteriorate the film quality of the silicon oxide film.

[0080] The third invention of the present application was made to solvesuch a problem.

[0081] That is, an object of the third invention is to provide a methodof forming a film, a coating unit, and an apparatus of forming a filmwhich, when obtaining a film by coating a coating liquid dispersedtherein starting material of film components of colloids or particles ina solvent on the substrate, enable to obtain a thin film of excellentquality such as an interlayer insulating film.

[0082] For this, the third method of forming a film comprises thefollowing steps as disclosed in claim 19:

[0083] a step of forming a film by coating a coating liquid, in whichparticles or colloids of the starting material of a film component aredispersed in a solvent, on a surface of a substrate under an atmospherefilled by the vapor of the solvent; and

[0084] a step of gelling the particles or colloids in the coated film;

[0085] wherein the vapor of the solvent contains one vapor of any one ofsolvent components.

[0086] As an example of a method of the third invention, a method offorming a film comprising the following steps can be cited:

[0087] a step of transferring a substrate into a treatment vessel froman inlet;

[0088] a step of closing the inlet of the treatment vessel;

[0089] a step of filling the treatment vessel with vapor of a solvent;

[0090] a step of coating a coating liquid in which particles or colloidsof the starting material of the film component are dispersed in thesolvent on the surface of the substrate in the treatment vessel filledby the vapor; and

[0091] a step of gelling the particles or the colloids in the coatedfilm.

[0092] As another example of the method of the third invention, a methodof forming a film comprising the following steps can be cited:

[0093] a step of disposing a substrate on a rotary stage by transferringinto the treatment vessel from the inlet;

[0094] a step of closing the substrate inlet of the treatment vessel;

[0095] a step of filling the vapor by feeding vapor of the solvent intothe treatment vessel;

[0096] a step of, together with rotating a rotary stage, spreading acoating liquid on the surface of the substrate by dispensing the coatingliquid, in which particles or colloids of the starting material of thefilm component are dispersed in the solvent, on a surface of thesubstrate; and

[0097] a step of gelling the particles or the colloids in the coatedfilm.

[0098] Further, a coating unit for carrying out this coating methodcomprises:

[0099] a treatment vessel accommodating a substrate;

[0100] a spin chuck holding the substrate disposed in the treatmentvessel;

[0101] a coating liquid nozzle dispensing a coating liquid on thesubstrate;

[0102] a coating liquid supply system dispensing a coating liquid, inwhich particles or colloids of starting material of film component aredispersed in the solvent, to the coating liquid nozzle;

[0103] a solvent nozzle dispensing the solvent into the treatmentvessel; and

[0104] a solvent supply system dispensing the solvent to the solventnozzle.

[0105] Further, an apparatus of forming a film for carrying out theaforementioned film forming method comprises:

[0106] a coating unit forming the film on the substrate comprising atreatment vessel accommodating a substrate, a spin chuck holding thesubstrate disposed in the treatment vessel, a coating liquid nozzledispensing the coating liquid to the substrate, a coating liquid supplysystem dispensing a coating liquid, in which particles or colloids ofthe starting material of film component are dispersed in the solvent, tothe coating liquid nozzle, a solvent nozzle dispensing the solvent intothe treatment vessel, and a solvent dispensing system dispensing thesolvent to the solvent nozzle;

[0107] an aging unit for gelling the coated film; and

[0108] a solvent replacement unit replacing the solvent in the coatedfilm.

[0109] The third invention, after a film is formed on a surface of asubstrate, while keeping an atmosphere therein the substrate is placedan atmosphere filled with vapor of the solvent, on the circumferenceportion of the substrate, a cleaning liquid of removing the coated filmmay be supplied to remove the coated film of the circumference portion.

[0110] In this case, the solvent contains a plurality kinds of organicsolvents. The third invention includes the case where the vapor is atleast one vapor of the plurality kinds of organic solvents.

[0111] For instance, the solvent contains ethylene glycol and alcohol,the vapor of the solvent is ethylene glycol. The starting material ofthe film component is a metal alkoxide, for instance.

[0112] Next, as the fourth invention, the inventors attempted to applythe aforementioned sol-gel method in an actual manufacturing line. Thatis, the inventors attempted to form a film by, in the step of forming afilm, dispensing a coating liquid, in which particles or colloids ofTEOS are dispersed in the solvent, on an approximately center ofrotation of the wafer surface, then by rotating the wafer around avertical axis, thereby spreading a coating liquid over the whole surfaceof the wafer by making use of centrifugal force of rotation.

[0113] Now, after the coating liquid is coated on the wafer,vaporization of the solvent is required to be suppressed not to disturbgelling of TEOS. For this, as one solvent components of the coatingliquid, a solvent, which has a high boiling point and is difficult toevaporate, such as ethylene glycol, is employed.

[0114] However, because of high viscosity of ethylene glycol, use of itas the solvent causes the viscosity of the coating liquid itself.

[0115] On the other hand, on the surface of the wafer thereon aninterlayer insulating film is formed, due to disposition of aluminumwiring, there is fine unevenness. Therefore, only by rotating the waferafter supply of the coating liquid on the surface of the wafer asdescribed above, the coating liquid is difficult to spread due to itsviscosity. Accordingly, the coating liquid is difficult to come into thefine unevenness of the surface of the wafer, thus, there occurs aproblem that a film is difficult to be coated on the whole surface ofthe wafer. In recent years, in particular, finer pattern is a trend. Asthe trend of the fine pattern advances and the width of aluminum wiringbecomes narrow, the coating liquid is the more difficult to come into.

[0116] The fourth invention of the present application was carried outto solve such a problem.

[0117] That is, an object of the fourth invention is to provide a methodof forming a film, a coating unit, and an apparatus of forming a film inwhich the coating liquid is easily coated on the surface of thesubstrate, thereby a film is formed universally all over the surface ofthe substrate, as a result, an excellent thin film such as an interlayerinsulating film can be obtained.

[0118] For this, a method of forming a film of the fourth inventioncomprises the following steps as disclosed in claim 26:

[0119] a step of coating the solvent of lower viscosity than the mostviscous component among the solvent components of the coating liquids inwhich particles or colloids of the starting material of the filmcomponent are dispersed in a solvent, and of capable of dissolving thestarting material, on the surface of the substrate;

[0120] a step of forming a film by coating the coating liquid on thesurface of the substrate; and

[0121] a step of gelling particles or colloids in the coated film.

[0122] Here, as a starting material, tetraethoxysilane can be employed.Further, after the step of gelling, on the surface of the substratethereon a film is formed, the other solvent than the aforementioned oneis supplied, thereby the solvent replacement step for replacing thesolvent in the coated film by the different solvent may be carried out.

[0123] Further, a coating unit for carrying out this film forming methodcomprises:

[0124] a treatment vessel accommodating a substrate;

[0125] a spin chuck holding the substrate disposed in the treatmentvessel;

[0126] a solvent nozzle dispensing solvent to the substrate;

[0127] a solvent supply system dispensing the solvent to the solventnozzle;

[0128] a coating liquid nozzle dispensing the coating liquid to thesubstrate thereto the solvent is supplied; and

[0129] a coating liquid supply system dispensing the coating liquid inwhich particles or colloids of the starting materials of film componentsare dispersed in the solvent to the coating liquid nozzle.

[0130] Further, an apparatus of forming a film for carrying out theaforementioned method for forming a film comprises:

[0131] a coating unit comprising a treatment vessel accommodating asubstrate, a spin chuck holding the substrate disposed in the treatmentvessel, a solvent nozzle dispensing solvent to the substrate, a solventsupply system dispensing solvent to the solvent nozzle, a coating liquidnozzle dispensing coating liquid to substrate thereto the solvent issupplied, and a coating liquid supply system dispensing the coatingliquid in which particles or colloids of the starting materials of filmcomponents is dispersed in the solvent to the coating liquid nozzle;

[0132] an aging unit for gelling the coated film; and

[0133] a solvent replacement unit for replacing the solvent in thecoated film.

[0134] In the method according to the fourth invention, in the step offorming a film, before coating a coating liquid on a substrate, asolvent of smaller viscosity than that of the component of the mosthighest viscosity among the components of solvent of the coating liquidis coated over the whole surface of the substrate. Accordingly, when thecoating liquid is supplied on the surface thereof, first, the startingmaterial of the coating liquid and water are dissolved in the solutioncoated over the whole surface of the substrate.

[0135] Thereby, due to mixing of the coating liquid and the solution,the viscosity of the coating liquid becomes low. Accordingly, thecoating liquid becomes easy to spread on the substrate, to be coatedover the whole surface of the substrate universally. As the result, athin film of excellent quality can be formed.

[0136] According to the method of the fourth invention, as a solution tobe coated on a surface of a substrate before coating the coating liquidon the surface of the substrate, one component of lower viscosity thanthe highest one among the aforementioned components of the solvent maybe employed. In this case, since one solvent component is coated, whenthe coating liquid is applied, this component and the coating liquid arelikely to be easily mixed. And, upon mixing thereof, there is nooccurrence of bubbles, accordingly a coated film of more excellentquality can be formed. Further, as a solution to be coated on thesurface of the substrate preceding the step of applying the coatingliquid on the surface of the substrate, alcohol can be employed. Sincealcohol can dissolve the aforementioned starting materials and water,effect as identical as the aforementioned method of the first disclosureof the fourth invention can be obtained.

[0137] Next, as the fifth invention, the inventors have studied a methodof forming an interlayer insulating film by use of the aforementionedsol-gel method.

[0138] In the case of applying the aforementioned sol-gel method in anactual manufacturing line, in the step of forming a film, the coatingliquid is supplied approximately the center of rotation on the surfaceof the wafer, then the wafer is rotated. Thus, by spreading the coatingliquid over the whole surface of the wafer by use of the centrifugalforce of rotation, a film is formed. In this case, the coating liquid ismade by mixing TEOS and the solvent in advance, the mixed liquid(coating liquid) is stored in a tank or the like, and the stored coatingliquid is supplied on the surface of the wafer.

[0139] However, in the case of a film being formed with the coatingliquid formed in advance and stored in a tank, there are some caseswhere unevenness of the film thickness or film quality is confirmed byeye-inspection. According to observation by the inventors, in the caseof the coating liquid which has stood for a certain degree of timeperiod after mixing of TEOS and the solvent being coated on the wafer,deterioration of the film quality was experientially confirmed to occur.This is a problem.

[0140] The fifth invention of the present application was made to solvesuch a problem.

[0141] That is, an object of the fifth invention is to provide a methodof forming a film which can suppress deterioration of the film qualityof the coated film, as a result, can obtain a thin film such as aninterlayer insulating film of excellent quality.

[0142] For this, a method of forming a film of the fifth inventioncomprises the following steps as disclosed in claim 32:

[0143] a step of mixing a first liquid containing particles or colloidsof a starting material of a film component which is insoluble ordifficult to be dissolved in water and water, and a second liquidconsisting of an organic solvent which can dissolve water and the filmcomponent;

[0144] a step of coating, after completion of the aforementioned mixing,before lapse of time in which the quality of the film obtained by themixing deteriorates, the mixed liquid containing the first liquid andthe second liquid on the surface of the substrate; and

[0145] a step of gelling the particles or the colloids in the filmcoated on the substrate.

[0146] According to the method of the fifth invention, after mixing ofthe first liquid and the second liquid, before lapse of the time periodwhere the film quality of the obtained coated film deteriorates, within6 min. after mixing for instance, the coating liquid is coated on thesurface of the substrate. Thereby, the film quality of the coated filmcan be suppressed from deterioration, resulting in an excellent thinfilm such as a silicon oxide film.

[0147] In this fifth invention, after a step of coating the mixed liquidwhich does not stand the deterioration time of the film quality aftercompletion of mixing of the first and the second liquids, before coatingof the mixed liquid on the surface of the next substrate, a step ofcleaning the mixing portion of the first and second liquids and theinsides of the liquid path at the down-stream of the mixing portion withan organic solvent such as alcohol may be carried out.

[0148] In this case, the mixed liquid which remained in the liquid pathand lapsed the film quality deteriorating time after mixing is clearedaway by the organic solvent. Therefore, upon treatment of the nextsubstrate, the old mixed liquid remaining in the liquid path is notcoated, accordingly deterioration of the film quality can be suppressed.

[0149] Further, when alcohol is employed as the organic solvent, sincealcohol dissolves the starting materials of the film components andwater, cleaning of the insides of the liquid path can be carried outreadily.

[0150] Next, as the sixth invention, the inventors have studied anothermethod of forming a film with use of the aforementioned sol-gel method.

[0151] That is, in the aforementioned sol-gel method, after coating ofthe coating liquid on the wafer, by standing for one night, forinstance, the coated film is gelled. However, for mass production,gelation should be carried out as fast as possible. As one method forthis, heating of the wafer may be one candidate, however, in this case,the solvent in the coated film is activated in evaporation.

[0152] For this, the inventors have studied, as the sixth invention, ofcarrying out gelation at, for instance, room temperature with use ofammonium gas (NH₃) containing water vapor.

[0153] The reason of containing moisture in ammonium gas is as follows.That is, a part of ammonium gas containing water vapor, upon sticking onthe coated film, is ionized such as

NH₃+H₂O→NH₄ ⁺+OH⁻.

[0154] That is, under presence of water, hydroxide group is formed to bebasic. An alkali is a catalyst accelerating polycondensation andcontributes to gelation. From this, water vapor is necessary to becontained. And, as the state approaches the saturated state due to muchwater vapor, OH groups can be expected to be generated much, accordinglythe rate of gelation is considered to be fast.

[0155] In FIG. 35, a device being used when gelation is carried out withammonium gas containing water vapor close to the saturated state isillustrated.

[0156] The device 501 comprises a disposing stage 511 of an wafer W, atreatment vessel 510 capable of tight sealing consisting of a sealingmember 512 and a cover 513, a tank 521 storing commercial ammonia water(NH₄OH) (concentration of ammonia: 30% by weight at normal temperature)520, a bubbling gas supply pipe 522 of carrying out bubbling byintroducing ammonia gas into ammonia water 520 in the tank 521, anexhausting outlet 523 of exhausting the treatment gas generated bybubbling, and a piping 525 communicating the exhausting outlet 523 andthe gas introducing inlet 514 disposed at the disposing stage 511.

[0157] At normal temperature, ammonia water contains approximately 33%by weight of ammonia as saturated concentration. Therefore, if thebubbling is started at normal temperature with the commercial ammoniawater as it is, first, ammonia gas is absorbed in the ammonia water.During this, ammonia gas is not generated or is not generated enough toobtain desired flow rate if generated, accordingly gelation takes a longtime. And, when the concentration of ammonia in the ammonia waterattains approximately 33% by weight, the ammonia gas containing watervapor of approximately saturated concentration is generated as atreatment gas. The generated treatment gas is introduced into thetreatment vessel 510 through the piping 525 and is exhausted out throughan exhausting path 515 opened at a cover 513 of the treatment vessel510.

[0158] However, in this device, as mentioned above, the commercialammonia water is employed as it is. Therefore, when continuous treatmentof the wafer is implemented, if ammonia water 520 in the tank 521 isreplenished, the concentration of the ammonia water 520 is temporarilylowered and ammonia gas is absorbed. Accordingly, ammonia gas is notgenerated or, if generated, the desired flow rate can not be obtained.Therefore, there is a problem that gelation can not be completed,accordingly, the desired film thickness and film quality can not beobtained.

[0159] As a method preventing this from occurring, such a method isconsidered that, immediately before replenishment of ammonia water,gelling treatment is interrupted, and, after the treatment gas begins tobe generated again, gelling is started again. However, upon carrying outlike this, there occurs a problem that serviceability ratio of thedevice goes down, thereby through-put also goes down.

[0160] The sixth invention of the present application is made to solvesuch a problem.

[0161] That is, an object of the sixth invention is, upon gelling thecoated film with an ammonia gas, to provide a gas treatment methodcapable of carrying out stable treatment, and capable of treating evenlybetween subjects to be treated.

[0162] Another object of the sixth invention is to provide a methodcapable of carrying out stable treatment, without restricting in thecase of carrying out gelling treatment with an ammonia gas, also in thecase of carrying out treatment to the subjects to be treated with thetreatment gas.

[0163] For this, the method of forming a film of the sixth inventioncomprises the following steps as disclosed in claim 36:

[0164] a step of forming a film by coating a coating liquid, in whichparticles or colloids of a starting material of a film component isdispersed in a solvent, on a surface of a substrate; and

[0165] a step of gelling the particles or colloids in the coated film byexposing the substrate to the ammonia gas;

[0166] wherein in the step of gelling, an ammonia gas is generated bysuccessively introducing the ammonia gas into at least 2 vesselsaccommodating ammonia water of ammonia concentration lower than thesaturated concentration, the ammonia gas generated precedently issupplied to the substrate, thereafter the succeedingly generated ammoniagas is supplied to the substrate, thereby conductance of the ammonia gassupplied to the substrate is maintained constant.

[0167] Further, an aging unit for carrying out the method of forming afilm comprises:

[0168] a treatment vessel accommodating a substrate;

[0169] a plurality of ammonia containers accommodating ammonia water;

[0170] bubbling gas supply systems feeding a carrier gas for bubbling inthe respective ammonia containers;

[0171] bubbling gas valves closing or opening the respective bubblinggas supply systems;

[0172] exhausting systems for exhausting gas generated in the respectiveammonia containers;

[0173] exhausting system valves for closing or opening the respectiveexhausting systems;

[0174] ammonia gas supply systems for feeding gas generated at therespective ammonia containers to the treatment vessels;

[0175] ammonia gas valves closing or opening the respective ammonia gassupply systems; and

[0176] a means for opening the respective bubbling gas valves in turn,at the same time, synchronizing with this closing or opening of therespective bubbling gas valves, closing respective exhausting systemvalves in turn, and opening the respective ammonia gas valves in turn.

[0177] Further, an apparatus of forming a film for carrying out theaforementioned method of forming a film comprises:

[0178] a coating unit for coating a coating liquid on a substrate;

[0179] an aging unit comprising a treatment vessel accommodating asubstrate, a plurality of ammonia containers accommodating ammoniawater, bubbling gas supply systems feeding a carrier gas for bubbling tothe respective ammonia containers, bubbling gas valves closing oropening the respective bubbling gas supply systems, exhausting systemsfor exhausting gas generated from the respective ammonia containers,exhausting system valves for closing or opening the respectiveexhausting systems, ammonia gas supply systems feeding the gas generatedat the respective ammonia containers to the treatment vessel, ammoniagas valves closing or opening the respective ammonia gas supply systems,and a means which opens in turn the respective bubbling gas valves, atthe same time, synchronizing with closing or opening of the respectivebubbling gas valves, closes in turn the respective exhausting systemvalves, and opens in turn the respective ammonia gas valves; and

[0180] a solvent replacement unit for replacing the solvent in thecoated film.

[0181] Here, since the concentration of ammonia in ammonia water islower than the saturated concentration, when ammonia water isreplenished, ammonia gas, upon bubbling by it, is absorbed by ammoniawater for a while. Therefore, it takes some time for ammonia gascontaining vapor of moisture to be generated with stability.

[0182] According to the sixth invention, when ammonia water isreplenished in the precedent container, the first container, forinstance, ammonia gas is being generated from the succeeding container,the second container, for instance, accordingly supply of the ammoniagas containing vapor of moisture is not interrupted, thereby stabletreatment can be carried out.

[0183] Further, by equalizing conductance of the path when gas flowsfrom the precedent container through the treatment vessel, conductanceof the path when gas flows from the precedent container through thefirst exhausting path, conductance of the path when gas flows from thesucceeding container through the treatment vessel, and conductance ofthe path when gas flows from the succeeding container through the secondexhausting path, upon switching the path, fluctuation of flow rate andpressure of ammonia gas can be suppressed. Therefore, more stabletreatment can be carried out.

[0184] Further, a method of forming a film of the sixth inventioncomprises the following steps as disclosed in claim 41:

[0185] a step of forming a film by coating a coating liquid, in whichparticles or colloids of a starting material of a film component isdispersed in a solvent, on a surface of a substrate; and

[0186] a step of gelling the particles or the colloids in the coatedfilm by exposing the substrate to ammonia gas;

[0187] wherein the gelling step comprises:

[0188] a preliminary exhausting step of exhausting treatment gas fromgas source without going through the treatment vessel but through theexhausting path;

[0189] a step of transferring the subject to be treated into thetreatment vessel; and

[0190] a treatment step of treating a subject to be treated by feedingthe treatment gas from the gas source into the treatment vessel byswitching the path from the exhausting path to treatment vessel side;

[0191] wherein the conductance of the path upon flowing through thetreatment vessel from the gas source and conductance of path uponflowing through exhausting path are made equal.

[0192] According to the sixth invention, fluctuation of the flow rateand pressure of the gas can be suppressed when the path of the gas isswitched, accordingly stable treatment can be carried out.

[0193] Next, the seventh invention will be described.

[0194] When the sol-gel method as described above is being applied in anactual manufacturing line, a coating unit for coating a coating liquidon an wafer, a gelling unit for gelling the coated film, and areplacement unit for replacing the solvent in the coated film by anothersolvent are necessary.

[0195] In addition, a pre-treatment unit for carrying out pretreatmentsuch as hydrophobic treatment to the wafer, and a bake unit for dryingthe wafer are also necessary. The device is constituted by furtherdisposing a transferring mechanism for transferring the wafer betweenrespective units.

[0196] Now, when the coating liquid is coated on the wafer, the solvent,being organic solvent, evaporates. If the amount of evaporation is much,there is a problem that the aimed film thickness and film quality cannot be obtained.

[0197] The seventh invention of the present application is made to solvesuch a problem.

[0198] That is, an object of the seventh invention is to provide anapparatus for forming a film capable of carrying out the following stepas soon as possible after coating a coating liquid in which particles orcolloids of a starting material of a film components are dispersed in asolvent on a substrate and capable of obtaining an excellent thin filmsuch as interlayer insulating film, for instance.

[0199] Therefore, the apparatus of forming a film of the seventhinvention comprises, as disclosed in claim 44: a coating portion offorming a film by coating a coating liquid, in which particles orcolloids of a starting material of a film components is dispersed in asolvent, on a substrate; a gelling treatment portion which is disposedin neighborhood of this coated portion and gels the particles or thecolloids in the coated film formed on the coated portion; a plurality ofpre-treatment portions for pre-treating prior to coating of the coatingliquid on the substrate; a plurality of heating portions for drying thesubstrate after treatment at the gelling treatment portion; a receivingportion receiving the substrate from the outside; a main transferportion which, in addition to transferring to the coating portionthrough the pre-treatment portion after reception of the substrate fromthe receiving portion, transfers the substrate after treatment at thegelling treatment portion to the heating portion; and an auxiliarytransfer portion transferring the substrate coated at the coatingportion to the gelling treatment portion.

[0200] According to the seventh invention, the substrate is transferredby an exclusive auxiliary transferring portion from the coating portionto the gelling treatment portion. Therefore, the substrate, immediatelyafter the coating liquid is applied, is transferred to the next step,thereby evaporation of the solvent can be suppressed, resulting in athin film of excellent film quality.

[0201] Here, in the aforementioned apparatus for forming a film, on thetransferring path of the substrate in the auxiliary transferringportion, a means for feeding vapor of solvent component, for instance,ethylene glycol, can be provided with. Further, a case for covering thecoating portion and gelling treatment portion, and a means for feedingvapor of the solvent component into the case may be provided with. Inthis case, evaporation of the solvent in the coated film duringtransferring of the substrate can be further suppressed.

[0202] In the aforementioned apparatus for forming a film, a solventreplacement treatment portion which is disposed neighboring the gellingportion, supplies another solvent different from the aforementionedsolvent to the substrate treated at the gelling treatment portion, andreplaces the solvent in the coated film by another solvent, can beprovided, and the substrate treated at the gelling treatment portion maybe transferred to the solvent replacement treatment portion by anauxiliary transferring portion. In this case, since the time periodduring which large surface tension of the solvent is added on thereticular structure of TEOS is made short, collapse of the filmstructure is suppressed, resulting in a thin film of excellent quality.

BRIEF DESCRIPTION OF THE DRAWINGS

[0203]FIG. 1 is a plan view showing diagrammatically total configurationof one example of an apparatus of forming a film being employed inpracticing the first invention.

[0204]FIG. 2A, FIG. 2B, FIG. 2C and FIG. 2D are diagrams for explainingflow of treatment of formation of a film in which the aforementionedapparatus of forming a film is employed.

[0205]FIG. 3 is a diagram diagrammatically showing one example of anaging unit and a gas feeding means in the aforementioned apparatus offorming a film.

[0206]FIG. 4 is a flow chart showing one example of flow of gellingtreatment according to the method of the first invention.

[0207]FIG. 5 is a characteristic diagram showing change on standing ofwafer temperature and concentration of solvent vapor during the gellingtreatment according to the method of the first invention.

[0208]FIG. 6 is a diagram showing diagrammatically another example ofthe gas feeding means.

[0209]FIG. 7 is a diagram showing diagrammatically another example ofthe gas feeding means.

[0210]FIG. 8 is a characteristic diagram showing change on standing ofwafer temperature and concentration of solvent vapor during the gellingtreatment in the case of the gas feeding means shown in FIG. 7 beingemployed.

[0211]FIG. 9 is a diagram showing diagrammatically another example ofthe gas feeding means.

[0212]FIG. 10A, FIG. 10B and FIG. 10C are diagrams for explainingsituation of variation of a coated film in sol-gel method.

[0213]FIG. 11 is a diagram showing diagrammatically one example of anaging unit being studied by the inventors.

[0214]FIG. 12 is a side view of a profile showing one example of asolvent replacement unit where a step of solvent replacement of thesecond invention is practiced.

[0215]FIG. 13 is a plan view showing a nozzle for solvent supply beingemployed in the aforementioned solvent replacement unit.

[0216]FIG. 14 is a diagram showing sequence of timings of closing andopening of valves for explaining a method of the second invention.

[0217]FIG. 15 is a side view of a profile showing another example of asolvent replacement unit where a step of solvent replacement of thesecond invention is practiced.

[0218]FIG. 16 is a plan view showing a solvent dispensing portion beingemployed in the solvent replacement unit.

[0219]FIG. 17 is a side view of a profile showing still another exampleof a solvent replacement unit where a step of solvent replacement of thesecond invention is practiced.

[0220]FIG. 18 is a cross-sectional view showing a conventional resistcoating device.

[0221]FIG. 19 is a side view of a profile showing an apparatus offorming a film being employed when practicing a method of the thirdinvention.

[0222]FIG. 20 is a plan view of a cross-section cut along A-A of thecoating unit of FIG. 19.

[0223]FIG. 21A, FIG. 21B and FIG. 21C are process diagrams showingsequentially a part of one example of processes of a method of the thirdinvention.

[0224]FIG. 22A, FIG. 22B and FIG. 22C are process diagrams showingprocesses following the processes shown in FIG. 21A to FIG. 22C.

[0225]FIG. 23 is an exploded diagram showing a situation where thecoated film of the circumference portion of an wafer is removed byedge-rinse treatment.

[0226]FIG. 24A and FIG. 24B are process diagrams showing processes aftercoating treatment.

[0227]FIG. 25 is a side view of a profile showing one example in which athree-way valve is attached to a solvent vapor feeding pipe of thecoating unit in the apparatus of forming a film.

[0228]FIG. 26 is a side view of a profile showing one example of acoating unit where the process of forming a film of the method of thefourth invention is practiced.

[0229]FIG. 27A, FIG. 27B, FIG. 27C and FIG. 27D are process diagrams forexplaining the solvent replacement process of the method of the fourthinvention.

[0230]FIG. 28A and FIG. 28B are process diagrams for explaining agelling process and a solvent replacement process of the fourthinvention.

[0231]FIG. 29 is a side view of a profile showing one example of acoating unit where the treatment forming a film of the method of thefifth invention is carried out.

[0232]FIG. 30A, FIG. 30B, FIG. 30C and FIG. 30D are process diagrams forexplaining the treatment of forming a film.

[0233]FIG. 31 is a characteristic diagram showing relation betweencoating liquids and film quality of the coated film.

[0234]FIG. 32 is a diagram showing diagrammatically one example of anaging unit in the apparatus of forming a film employed upon practicingof the method of the sixth invention.

[0235]FIG. 33 is a diagram showing diagrammatically one example of pathof gas flow in the aging unit shown in FIG. 32.

[0236]FIG. 34 is a diagram showing diagrammatically another example ofpath of gas flow in an aging unit.

[0237]FIG. 35 is a diagram showing diagrammatically a conventional agingunit.

[0238]FIG. 36 is a plan view showing one example of one embodiment of anapparatus of forming a film of the seventh invention.

[0239]FIG. 37 is a cross-sectional view showing one example of acoating/aging unit of the apparatus of forming a film.

[0240]FIG. 38 is a cross-sectional view showing one example of thecoating unit of the coating/aging unit.

[0241]FIG. 39 is a cross-sectional view showing one example of the agingunit of the coating/aging unit.

[0242]FIG. 40 is a cross-sectional view showing one example of a solventreplacement unit of the apparatus of forming a film.

[0243]FIG. 41 is a plan view showing another example of a coating/agingunit.

[0244]FIG. 42 is a perspective view showing another example of acoating/aging unit.

[0245]FIG. 43 is a plan view showing another example of an apparatus offorming a film.

[0246]FIG. 44 is a plan view showing still another example of anapparatus of forming a film.

[0247]FIG. 45 is a plan view showing still another example of anapparatus of forming a film.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0248] In the following, the details of specific examples of the presentinvention will be described with reference to drawings. Incidentally,the scope of the present invention should not be construed to berestricted to the range of the following examples.

EXAMPLE 1

[0249]FIG. 1 is a plan view showing diagrammatically an apparatus offorming a film which is employed upon practicing the method of example 1involving the first invention of the present application. Referencenumeral 11 denotes an input/output port of wafers W which aresubstrates. At this input/output port 11, from a cassette C disposed ona cassette stage CS, a carrying arm 12, after pulling out an wafer W,supplies to a main arm 13.

[0250] On one side of guide rails 14 which is transferring path of amain arm 13, a coating unit 2 which is a coating portion constituting amain portion of the apparatus, together with an aging unit 3 which is agelling treatment portion and a solvent replacement unit 4 which is asolvent replacing portion, is arranged in this order. Also on the otherside of the transferring path 14, treatment units U1 to U4 are arranged.To these treatment units U1 to U4, units for carrying out hydrophobictreatment preceding coating of a coating liquid on the substrate,cooling treatment, and heat treatment (bake treatment) after formationof a film on the substrate or the like are assigned, respectively.

[0251] The whole operation of example 1 employing this apparatus offorming a film will be described.

[0252] In FIG. 2A to FIG. 2D, flow of treatment of forming a film isschematically shown following the order. An wafer W prior to treatmentwhich is taken out of the inside of a cassette C of a cassette stage CSby a main arm 13 is stored in a coating unit 2. And, in the coating unit2, a coating liquid T id dripped on a surface of the wafer W (FIG. 2A).As a coating liquid, one in which colloids and/or particles of TEOS, forinstance, is dispersed in a solvent containing ethylene glycol, ethylalcohol, water and a trace of hydrochloric acid can be employed.

[0253] Subsequently, the inside of the coating unit 2 is filled withvapor of the solvent, ethylene glycol, for instance. In this state, whenthe wafer W is rotated with high speed, the coating liquid is spreadover a surface of the wafer to form a coated film F (FIG. 2B).

[0254] Then, the wafer W is disposed on a heating plate 31 of the agingunit 3, followed by closing of a cover 33 to seal. At this time, thewafer W is heated to a predetermined temperature, approximately 100° C.,for instance, by the heating plate 31. Thereafter, vapor of ethyleneglycol and a carrier gas are introduced into the aging unit 3 to gel thecoated film (FIG. 2C).

[0255] Then, in the solvent replacement unit 4, with ethyl alcohol, HMDS(hexamethyl disilane) and heptane, solvent replacement of a gelled filmis carried out. By this solvent replacement, moisture in the coated filmis replaced by ethyl alcohol. Further, by HMDS, hydroxide groups in thecoated film are removed. Further, the solvent in the coated film isreplaced by heptane. The reason to employ heptane exists in that, due touse of a solvent of lower surface tension, stress added on a porousstructure, that is, a reticular structure of TEOS, can be reduced.Thereby, the reticular structure is prevented from collapsing. The stateup to this step is illustrated in FIG. 2D. Thereafter, the wafer W isprocessed for approximately 1 min., for instance, at a bake unit. Thus,on the surface of the wafer W, an interlayer insulating film consistingof silicon oxide film of a thickness of 6000 A, for instance, is formed.

[0256] In FIG. 3, one example of the aging unit (gelling treatmentportion) 3 and a gas feeding means 5, both of which are essentialportions of the present example, is shown. As shown in FIG. 3, the gasfeeding means 5 is connected to a gas introducing path 34 of the agingunit 3.

[0257] The gas feeding means comprises a gas mass flow controller 51, aliquid mass flow controller 52, a vaporizer 53, a 3-way valve 54 andpipes or tubes connecting them.

[0258] The gas mass flow controller 51 controls flow rate of the carriergas consisting of a nitrogen gas or an ammonia gas delivered from acarrier gas feeding device (not shown in the figure).

[0259] The liquid mass flow controller 52 controls the flow rate of thesolvent such as ethylene glycol delivered from a solvent dispensingdevice (not shown in the figure).

[0260] A vaporizer 53 vaporizes the solvent controlled in flow rate bythe gas mass flow controller 51 and the liquid mass flow controller 52.

[0261] The 3-way valve 54 switches the direction of delivery of the gascontaining vapor of the solvent component vaporized by the vaporizer 53between the chamber side and the exhaust side of the aging unit 3.

[0262] The aging unit 3 has a configuration identical with the unitshown in FIG. 11.

[0263] Therefore, a detailed description of the aging unit 3 is omittedhere. Incidentally, the gas from the gas introducing path 34 isdispersed in a dispersing room 34 a and is introduced into a treatmentspace from a gas introducing inlet 34 b formed in slit along thecircumference direction.

[0264] Next, flow of the gelling treatment will be described.

[0265]FIG. 4 shows a flow-chart of the gelling treatment. First, a 3-wayvalve 54 is switched toward the exhaust side. Then, a carrier gas and asolvent are supplied from a carrier gas supply device (not shown in thefigure) and a solvent supply device (not shown in the figure),respectively. Then, at the vaporizer 53, a gas mixture of vapor of thesolvent component and the carrier gas is formed. Thus generated gasmixture is exhausted through the 3-way valve 54 (step 1).

[0266] When the state of generation such as concentration, temperatureor the like of the gas mixture became stable, in the coating unit 2, thewafer W coated thereon a film is placed on the heating plate 31 kept atthe predetermined temperature and the cover 33 is closed (step 2).

[0267] Then, the 3-way valve 54 is switched toward the chamber side. Fora while after being switched toward the chamber side, that is, until thegas introducing path 34 of the aging unit 3 and the inside of thetreatment chamber S are filled by the gas mixture, the concentration ofthe solvent component in the gas mixture is adjusted to be the saturatedconcentration at the treatment temperature, for instance, 100° C. (timeA in FIG. 5).

[0268] Then, after the temperature of the wafer W is raised graduallyfrom the normal temperature to fill the insides of the treatment chamberS by the gas mixture, until the temperature of the wafer W reaches thepre-determined temperature To, for instance, 100° C., the averageconcentration of the solvent component in the gas mixture is made low(time B in FIG. 5). During the period where the solvent concentration islow, the concentration of the solvent component is continuously raisedas the wafer temperature is elevated. The concentration of the solventcomponent is preferably controlled such that the partial pressure of thesolvent component is always equal with the saturated vapor pressure atthe wafer temperature, that is, 100% (step S3).

[0269] Incidentally, the concentration control of the solvent componentmay be carried out by controlling the flow rate of the carrier gas withthe gas mass flow controller 51. Or, it can be carried out throughcontrol of the liquid mass flow controller 52. Further, both of them maybe employed simultaneously.

[0270] When the temperature of the wafer W attained the predeterminedtemperature, the concentration of the solvent component is controlled tobe the saturated concentration (100%) (step 4). Then, this state ismaintained until gelling treatment of the coated film is completed (timeC in FIG. 5). Thereafter, by switching the 3-way valve 54 toward theexhaust side, the gas mixture sent from the vaporizer 53 is exhausted(step S5). Then, by opening the cover 33 of the aging unit 3, the waferW is carried out of the aging unit 3 (step 6). Thereby, the gellingtreatment is completed.

[0271] According to the example 1, since, after the state of generationof the gas mixture became stable, the gas mixture is supplied into asealed container of the aging unit 3, at the start of gas introduction,fluctuation of the concentration and the temperature of the solventcomponent can be suppressed. Further, until the temperature of the waferis elevated to the pre-determined temperature after the wafer is carriedinto the sealed container, the gas concentration of the solventcomponent in the gas mixture is gradually elevated corresponding to thetemperature of the wafer. Therefore, the gas of the solvent componentcan be prevented from condensing immediately after carrying in of thewafer W into the sealed container, thereby excellent thin film such asan interlayer insulating film can be obtained.

[0272] In FIG. 6, another example of the gas feeding means isillustrated. As shown in FIG. 6, the gas feeding means 6 comprises a gasmass flow controller 61, a 2-way valve 62, a chamber 63, a heater 64, afeeding pipe 65, a gas mass flow controller 66, a 2-way valve 66 a, a2-way valve 67, and pipes or tubes connecting therebetween.

[0273] The gas mass flow controller 61 controls the flow rate of thecarrier gas consisting of a nitrogen gas, an ammonia gas or the like fedfrom the carrier gas feeder (not shown in the figure).

[0274] The 2-way valve 62 switches feeding or stoppage of the carriergas regulated in flow rate by the gas mass flow controller 61 to achamber of the aging unit 3.

[0275] The container 63 stores the solvent such as ethylene glycol orthe like.

[0276] The heater 64 heats the solvent.

[0277] The feeding pipe 65 is to pass a bubbling gas such as a nitrogengas (N₂ gas) fed from the bubbling gas feeder (not shown in the figure)into the solvent such as ethylene glycol solution.

[0278] The gas mass flow controller 66 is to control the flow rate ofthe solvent vapor generated by a container 63 which is a heatingbubbler.

[0279] The 2-way valve 66 a is to carry out switching between feed andstoppage of the solvent vapor controlled in flow rate by the mass flowcontroller 66.

[0280] The 2-way valve 67 switches exhaust and stoppage of the solventvapor generated by the heating bubbler.

[0281] The carrier gas and the solvent vapor are fed into the chamber 3after mixing.

[0282] In the case of the gas feeding means shown in FIG. 6 beingemployed, at the same time with opening of the 2-way valves 62 and 66 a,the 2-way valve 67 of the solvent vapor line is closed, for instance,and, by operating either one or both of the mass flow controllers 61,66, the concentration of the solvent component in the gas mixture can bevaried continuously. However, if the flow rate of the bubbling gas (N₂)is held constant, while exhausting the vapor by opening the 2-way valve67, only the necessary flow rate may be flowed by controlling the massflow controller 66. In this case, the pressure in the container 63 isadvantageously stabilized. Further, by opening the 2-way valve 67 of thesolvent vapor line and by squeezing the 2-way valve 66 a to make zerothe flow rate, feed of the solvent vapor to the chamber 3 can bestopped. Incidentally, if the mass flow controllers 61, 66 have acomplete shut-off function, 2-way valves 62 and 66 a can be dispensedwith.

[0283] And, also in the example illustrated in FIG. 6, the concentrationof the solvent component in the gas mixture can be continuouslycontrolled corresponding to the wafer temperature. As illustrated in theaforementioned FIG. 5, for instance, the concentration of ethyleneglycol is controlled. Further, before the wafer W is carried in, asidentical as the aforementioned example, the solvent vapor of ethyleneglycol is kept being generated and exhausted. Therefore, upon startinggas introduction, fluctuation of the temperature and the concentrationof the solvent component can be suppressed, in addition, condensation ofthe gas of the solvent component due to low temperature of the wafer isprevented from occurring, thus, the excellent thin film such as aninterlayer insulating film can be obtained.

[0284] Further, the gas feeding means 7 shown in FIG. 7 is one in whichthe mass flow controller 61 of the carrier gas line is omitted from thegas feeding means 6 shown in FIG. 6. Other constitution is identical asthe gas feeding means 6 shown in FIG. 6.

[0285] In this case, in order to control the concentration of thesolvent component in the gas mixture, in a state where the 2-way valve62 of the carrier gas line is opened and the flow rate of the solventcomponent is controlled by the mass flow controller 66, opening/closingof the 2-way valve 67 of the solvent vapor line may only be switchedappropriately.

[0286] That is, as shown in FIG. 8, until the wafer W is carried in thechamber 3 and, after the inside of the gas introducing path 34 and thetreatment chamber S are filled with the gas mixture, the temperature ofthe wafer is elevated to the pre-determined temperature, for instance,approximately 100° C. (time B in FIG. 8), the 2-way valve 67 is switchedto the chamber 3 side intermittently. Thereby, the time-averagedconcentration of the solvent component in the gas atmosphere in thechamber 3 can be adjusted. This time, in the time interval B as shown inFIG. 8, by making relatively and gradually longer the timings ofswitching of the 2-way valve 67 toward the chamber 3 side, the averageconcentration of the solvent component in the gas atmosphere in thechamber 3 can be controlled to be an appropriate concentrationcorresponding to the elevation of the wafer temperature. Incidentally,in FIG. 8, conductance of the gas flow path is ignored and depiction ismade by assuming that the concentration of the gas varies correspondingto the switching of the valve 67.

[0287] In this case also, before carrying in of the wafer W, it ispreferable the solvent vapor to be kept being generated and exhausted.Also in this example, fluctuation of the concentration and thetemperature of the solvent component can be suppressed at the start ofgas introduction, further, condensation of the gas of the solventcomponent due to the wafer of low temperature can be prevented fromoccurring. Thereby, an excellent thin film such as an interlayerinsulating film can be obtained. Further, in the example shown in FIG.7, by disposing a temperature controlled buffer room 71, theconcentration fluctuation of the solvent vapor can be averaged.

[0288] Further, the gas feeding means 8 shown in FIG. 9, in the gasfeeding means 7 shown in FIG. 7, in place of the mass flow controller 66and the 2-way valve 67, is provided with a 3-way valve 81 which flowsthe solvent vapor to any one of the chamber 3 side and the exhaust side.By switching appropriately the feeding direction of the solvent vaporbetween the chamber 3 side and the exhaust side, the solvent vapor canbe intermittently fed to the chamber 3 as shown in FIG. 8. Thereby, theconcentration of the solvent component in the gas atmosphere in thechamber 3 can be controlled such that the appropriate concentrationcorresponding to the temperature rise of the wafer is attained.

[0289] Incidentally, in all of FIGS. 3, 6, and 7, from generation of thesolvent vapor to the chamber, the piping can be heated with an object toprevent condensation in the piping from occurring.

[0290] In the above, in the first invention, the means for generatingthe solvent vapor is not restricted to a heating bubbler. Further, inthe gas feeding means 6 and 7 shown in FIG. 6 and FIG. 7, the carriergas line is dispensed with. In the case where there is no carrier gasline, at the heating bubbler, the solvent concentration and the flowrate of the bubbling gas may be controlled. Further, as the substrate tobe subjected to treatment, without restricting to the wafer, the glasssubstrate for liquid crystal display can be employed.

[0291] Thus, according to the first invention, fluctuation of theconcentration and the temperature of the solvent component can besuppressed at the beginning of gas introduction. Further, condensationof the gas of the solvent component can be prevented from occurringimmediately after carrying in the substrate, thereby the excellent thinfilm such as the interlayer insulating film can be obtained.

[0292] In the following, Example 2 involving the second invention willbe described. Incidentally, in the following examples, the partsrepeating the preceding examples are omitted from explanation.

EXAMPLE 2

[0293] In such an apparatus of forming a film as shown in FIG. 1, thewafer W, after being subjected to hydrophobic treatment and coolingtreatment, is sequentially carried to the coating unit 2, aging unit 3,and solvent replacement unit 4 by the main arm 13, and, after beingcarried out respective pre-determined treatments at these units, baketreatment is carried out.

[0294] The steps of forming a film and gelling carried out at thecoating unit 2 and the aging unit 3, respectively, will be brieflydescribed with reference to FIG. 2A to FIG. 2D.

[0295] In the step of forming a film, in order to suppress vaporizationof the solvent in the coating liquid, in the not shown treatment chamberfilled with the vapor of ethylene glycol for instance, on theapproximately rotation center portion on the surface of the wafer Wsucked to the spin chuck 21, the coating liquid T is fed (FIG. 2A).Next, by rotating the wafer W, the coating liquid T is spread over thewhole surface of the wafer due to the centrifugal force to form a film(FIG. 2B). Here, the coating liquid T is one in which colloids orparticles of TEOS which is a metal alkoxide are dispersed in solventsuch as ethylene glycol or ethyl alcohol, for instance, and water and atrace of hydrochloric acid are further contained.

[0296] Further, in the gelling step, the colloids of TEOS contained inthe coated film on the wafer is gelled to link the colloids inreticulum. Therefore, in the treatment chamber filled by vapor ofethylene glycol, the wafer W is heated to approximately 100° C. by theheating plate (FIG. 2C) Here, introduction of the vapor of ethyleneglycol into the treatment chamber is carried out to suppressvaporization of the solvent in the coated film. Therefore, it iscontrolled such that, at the temperature in the treatment chamber, forinstance, the vapor pressure becomes 100%.

[0297] In this gelling step, instead of heating, by carrying out thetreatment at normal temperature in the treatment chamber filled by anammonia gas, by use of the ammonia gas which is an alkali catalyst,gelling of the colloids of TEOS may be expedited.

[0298] Subsequently, the solvent replacement unit 4 will be describedwith reference to the side view of a profile of FIG. 12 and the planview of FIG. 13. In the figure, reference numeral 131 denotes a chuck ofholding an wafer W in a level position (an approximate level positioncan be included). This chuck 131 is constituted by a vacuum chuck forinstance and sucks and holds the wafer W. To the approximately centralportion of the bottom surface of the chuck 131, a rotation axis 133capable of being gone up and down and rotated by a driving portion 132is attached. With such a configuration, the chuck 131 is capable ofgoing up and down between a delivering position of the wafer W which isshown by the dotted line in the figure and is positioned above a cup tobe described later and a treatment position of the wafer W shown by thesolid line in the figure. Further, the chuck 131 is designed to berotated around a vertical axis.

[0299] In the circumference of the chuck 131 which is in the treatmentposition and the wafer W, a cup 134 is disposed to in order to surroundthese. On the upper surface of this cup 134, an opening 134 a where thewafer W is passable is formed. The opening 134 a can be opened andclosed by a cover 135 which is disposed such that it is capable of goingup and down. Further, at the bottom portion of the cup 134, a liquidexhaust path 136 a and an exhaust gas path 136 b are connected.

[0300] Inside the cup 134, above the outside of the wafer W when thechuck 131 holding the wafer W is in a treatment position, for instance,3 nozzles of 140A through 140C are disposed.

[0301] Among these nozzles 140A to 140C, 140A is the first nozzle ofdispensing alcohol such as ethanol on the surface of the wafer W.Similarly, 140B is the second nozzle of dispensing a hydrophobictreatment liquid such as HMDS. Further, the nozzle 140C is the thirdnozzle of dispensing a solvent such as heptane of smaller surfacetension than the solvent contained in the coating liquid. These nozzles140A through 140C are disposed with the same distance apart in thecircumference direction as shown in FIG. 13. These nozzles 140A through140C correspond to the respective solvent dispensing portions of thepresent invention.

[0302] These nozzles 140 (140A through 140C) are attached to the insidewall of the cup 134 with the respective attachments 141, and the tip endof each nozzle is attached slantingly to be directed toward theapproximately center of rotation O of the surface of the wafer W (thesurface thereon a coated film is formed). Therewith, from each nozzle140, as shown in the figure with the dotted lines, the solvent isdispensed around the center of rotation O of the surface of the wafer W.Further, the tip ends of these nozzles are positioned outside the waferW held by the chuck 131. Therefore, when the chuck 131 which holds thewafer W goes up and down, the wafer W and the each nozzle 140 aredesigned not to interfere each other.

[0303] The respective nozzles 140 are connected respectively to theethanol tank 143 a, HMDS tank 143 b, and heptane tank 143 c (not shownin FIG. 12) which are disposed outside the cup 134 by the solventdispensing path 142 (142 a through 142 c) inserted from the bottomsurface of the cup 134, for instance. The solvent dispensing paths 142 athrough 142 c are provided respectively with valves Va through Vc. Thesevalves Va through Vc are controlled in their timings of opening andclosing and the degree of opening by a controller 144.

[0304] In this solvent replacement unit 4, the step of solventreplacement is carried out as follows. That is, the cover 135 iselevated up to the position shown by the dotted line in FIG. 12. At thesame time, the chuck 131 is elevated up to the position above the cup134. Then, at the position shown by the dotted line in FIG. 12, by themain arm 13, the wafer W carried up to the unit 4 is delivered to thechuck 131. Then, the chuck 131 is lowered down to the treatmentposition. At the same time, the cover 135 is lowered down to close thecup 134. Thereafter, the wafer W is rotated. Subsequently, with thecontroller 144, the valve Va is opened, thereby ethanol is dispensedaround the center of rotation O of the surface of the wafer W from thefirst nozzle 140A. Due to centrifugal force, the ethanol diffuses overthe whole surface of the wafer W. Thereby, ethanol dissolves in themoisture in the coated film. As the result, the moisture is replaced bythe ethanol. Incidentally, preceding the rotation of the wafer W,ethanol may be dispensed around the center of rotation O of the surfaceof the wafer W.

[0305] After thus ethanol is dispensed on the surface of the wafer W,while rotating the wafer W, similarly the valve Vb is opened. Thereby,HMDS is dispensed on the surface of the wafer W from the second nozzle140B to make diffuse. Thereby, hydroxide groups in the coated film areremoved. Further thereafter, the valve Vc is opened to dispense heptaneon the surface of the wafer W from the third nozzle 140C to makediffuse. Thereby, the solvent in the coated film is replaced by heptane.The reason why to use heptane is to reduce the force added on the porousstructure namely reticular structure of TEOS by use of the solvent oflower surface tension, thereby the reticular structure of TEOS isprevented from collapsing.

[0306] Here, the timings of opening and closing of each valve Va, VB andVc are shown in FIG. 14. That is, immediately before closing the valveVa, the valve Vb is opened, further, immediately before closing thevalve Vb, the valve Vc is opened. That is, immediately before supply ofethanol completes, supply of HMDS is began. Similarly, immediatelybefore supply of HMDS completes, supply of heptane is started. Thus, itis designed such that a state in which supply of the solvent is stoppeddoes not occur when the solvent to be dispensed to the wafer W isswitched. Here, when 2 kinds of the solvents are being dispensedsimultaneously, by reducing the degree of opening of the valve of thesolvent of which supply is to be stopped, the flow rate of the solventmay be reduced.

[0307] Thus, the wafer W undergone the predetermined treatment at thesolvent replacement unit 4 is carried up to the bake unit by the mainarm 13. The wafer W is bake treated at this unit, thereby on the surfaceof the wafer W, an interlayer insulating film consisting of a siliconoxide film is formed.

[0308] According to the aforementioned example 2, since 3 pieces ofnozzles 104 corresponding to 3 kinds of solvents are attached inside thecup 134, without implementing opening and closing of the cover 135 andmovement of the nozzles 140, the solvent can be dispensed on the surfaceof the wafer W. Therefore, when the solvent to be dispensed to the waferW is switched, before stopping the supply of the preceding solvent,supply of the succeeding solvent is began, thereby a state in which bothsolvents are dispensed simultaneously can be realized. Thus, since thesolvents can be fed continuously, there is no time when the supply ofthe solvent is interrupted.

[0309] Thereby, inconvenient phenomena occurring due to interruption ofsupply of the solvent, that is, the phenomena such that, due to contactof the solvent on the surface of the wafer and air, the moisture in theair is confined in the coated film, or, the solvents vaporize, can beprevented from occurring in advance. As the result, the film structureof TEOS can be prevented from collapsing, an excellent silicon oxidefilm can be formed on the wafer W.

[0310] Further, in the example 2, the solvents can be dispensedcontinuously. Therefore, in the case of the preceding solvents beingreplaced, compared with the conventional method where opening andclosing of the cover and transfer operation of the carrying arm arenecessary, the time necessary for the whole solvent replacementtreatment can be made remarkably short, and the throughput of the wholetreatment can be improved. Further, thus, the time necessary for thesolvent replacement step can be made short. As the result, the timeperiod during which the large surface tension of the solvent is added onthe reticular structure of TEOS is made short. Therefore, also from thispoint of view, the film is suppressed from collapsing.

[0311] In the above example 2, upon dispensing ethanol, HMDS, andheptane, stoppage of supply of the preceding solvent and start of supplyof the succeeding solvent may be carried out simultaneously. Further, bymaking extremely short the time period between the stoppage of supply ofthe preceding solvent and the start of supply of the succeeding solvent,supply of the both solvents may be carried out continuously withoutessentially being interrupted. Even in such a case, supply of thepreceding solvent and the succeeding solvent is carried out withoutessentially being interrupted. As the result, the aforementionedinconvenient phenomena can be suppressed from occurring, thus anexcellent thin film can be formed on the substrate.

EXAMPLE 3

[0312] Next, another example of a solvent replacement unit for carryingout the solvent replacement step, that is, example 3 will be describedwith reference to FIGS. 15 and 16.

[0313] The different point of this solvent replacement unit from theaforementioned solvent replacement unit exists in that 3 kinds ofsolvents are dispensed on the surface of the wafer through a commonsolvent dispensing portion 150 arranged in a ring. The solventdispensing portion 150 is disposed inside the cup 134 and at the upperside of the outside of the wafer W when the chuck 131 holding the waferW is positioned at the treatment position, for instance. That is, thesolvent dispensing portion 150 arranged in a ring are t0 fixed to aplurality of places of the inside of the cup 134 through the attachmentmembers 151.

[0314] The inside of the solvent dispensing portion 150 is disposedslanted with an expanding diameter toward, for instance, the lower side.On this slanting surface, a plurality of dispensing holes 152 are formedalong a circumference direction with an equal distance apart. Thereby,the solvent from the respective dispensing hole 152 is dispensed onaround the center of rotation O of the surface of the wafer W. Further,the inside of the solvent dispensing portion 150 is positioned outsidethe wafer W held by the chuck 131. Therefore, when the chuck 131 holdingthe wafer W went up and down, the wafer W and the solvent dispensingportion 150 are designed not to interfere each other.

[0315] To this solvent dispensing portion 150, one end side of thesolvent dispensing path 153 inserted from, for instance, the bottomsurface of the cup 134 is connected. On the other hand, the other endside of the solvent dispensing portion 153 are branched, outside the cup134, for instance, into 3 dispensing paths 153 a through 153 c. Theother end sides of these branched dispensing paths 153 a through 153 care connected to a ethanol tank 154 a, a HMDS tank 154 b, and a heptanetank 154 c, respectively. To the branched dispensing paths 153 a through153 c, valves Va through Vc are inserted, respectively. The timing ofopening or closing and the degree of opening of these valves Va throughVc are controlled by a controller 144. Other configuration is identicalas the aforementioned example 2.

[0316] In this solvent replacement unit 4, after the wafer W is held bythe chuck 131, the cup 134 is closed. Thereafter, the valve Va is openedby the controller 144, ethanol is dispensed to the solvent dispensingportion 150 through the solvent dispensing paths 153 a and 153. Then,ethanol is dispensed in the neighbor of the center of rotation O on thesurface of the wafer W through the dispensing holes 152 from the solventdispensing portion 150. Then, as identical as the aforementionedembodiments, ethanol is diffused all over the whole surface of the waferW.

[0317] Then, by opening the valve Vb, HMDS is dispensed on the surfaceof the wafer W through the solvent dispensing paths 153 b, 153, and thesolvent dispensing portion 150. Subsequently, by opening the valve Vc,heptane is dispensed on the surface of the wafer W through the solventdispensing paths 153 c, 153, and the solvent dispensing portion 150. Inthis case, the timings of opening and closing of the valves Va, Vb, andVc are carried out identical as the above example 2.

EXAMPLE 4

[0318] Subsequently, still another example of the solvent replacementunit for carrying out the step of solvent replacement, that is, Example4, will be described with reference to FIG. 17. The different point ofthis solvent replacement unit from the aforementioned solventreplacement unit exists in that 3 kinds of solvents are dispensed on thesurface of the wafer through a common solvent nozzle 160.

[0319] The solvent nozzle 160 is disposed combined with the cover 135 insuch a manner that the tip end of the nozzle 160 pierces through thecover 135 of the cup 134 to oppose the neighborhood of the center ofrotation on the surface of the wafer W. Thereby, the solvent is ejectedin the neighborhood of the center of rotation of the surface of thewafer W. In this example, the solvent nozzle 160 corresponds to a commonsolvent dispensing portion.

[0320] To this solvent nozzle 160, one end side of the solventdispensing path 161 is connected. On the other hand, the other end sideof the solvent dispensing path 161 is branched into 3 dispensing paths161 a, 161 b, and 161 c. The other end sides of these brancheddispensing paths 161 a through 161 c are connected to a ethanol tank 162a, a HMDS tank 162 b, and a heptane tank 162 c .

[0321] Further, in the branched dispensing paths 161 a through 161 c,valves Va through Vc are inserted, respectively. These valves Va throughVc are controlled of their timings of opening and closing and theirdegree of opening through a controller 144. The other configuration isidentical as that of the aforementioned example.

[0322] In this example 4, after the wafer W is held by the chuck 131,the cup 134 is closed. Thereafter, the valve Va is opened by thecontroller 144, ethanol is dispensed in the neighborhood of the centerof rotation O of the surface of the wafer W through the solventdispensing portions 161 a and 161 b, and the solvent nozzle 160. Then,upon the valve Vb being opened, HMDS is dispensed on the surface of thewafer W through the solvent dispensing paths 161 b and 161, and thesolvent nozzle 160. Subsequently, upon the valve Vc being opened,heptane is dispensed on the surface of the wafer W through the solventdispensing paths 161 c and 161, and the solvent nozzle 160. Here, thetimings of opening and closing of the valves Va, Vb, and Vc areidentical as the example 2.

[0323] Even in the solvent dispensing units shown in these FIG. 15 andFIG. 17, ethanol, HMDS, and heptane are continuously dispensed on thesurface of the wafer W in this order through the common solventdispensing portion 150 or the nozzle 160. Therefore, the effectidentical as the case in which the solvent replacement unit shown inFIG. 12 is employed can be obtained. Further, the solvent dispensingportion shown in FIG. 15 and the solvent nozzle 160 shown in FIG. 17 maybe combined. That is, among the solvent dispensed through the solventdispensing portion 150, dispensing deficiency in the neighborhood of thecenter of rotation of the wafer W may be complemented by the supply dueto the solvent nozzle 160.

[0324] According to the second invention, in the method of forming afilm having a step of carrying out replacement of the solvent bydispensing a plurality of solvents on the substrate, the precedingsolvent and the succeeding solvent can be dispensed continuously. As theresult, an excellent thin film such as an interlayer insulating film canbe obtained.

EXAMPLE 5

[0325] Next, Example 5 involving the third invention of the presentapplication will be described.

[0326] In FIG. 19, an example of a coating unit 2 involving the thirdinvention is illustrated.

[0327] As shown in FIG. 19, the coating unit 2 comprises a cup 22 whichis a treatment chamber, a vacuum chuck 25 which is disposed inside thecup 22 and functions as a rotary stage holding the wafer, and a coatingliquid nozzle 26 for dispensing the coating liquid on the center portionof the wafer W.

[0328] On the upper surface of the cup 22, an open inlet for carrying ina substrate 22 a is disposed. This intake for taking in the substrate 22a is opened and closed by a cover 21 capable of freely going up or down.At the bottom surface of the cup 22, a breakthrough 22 b is disposed.From this breakthrough 22 b, a rotation axis 24 is inserted. The upperend of the rotation axis 24 is combined with the vacuum chuck 25, thelower end of the rotation axis is combined with a driving portion 23.Rotating driving force of the driving portion 23 is transmitted to thevacuum chuck 25 through the rotation axis 24. Further, the rotation axis24 is designed to be capable of going up or down.

[0329] To the cover 21, a coating liquid nozzle 26 of dispensing coatingliquid on the center portion of the wafer W is attached.

[0330] To the cup 22, solvent vapor dispensing pipes 27 for dispensingvapor of the solvent employed in the coating liquid are connected. Onthe base side of the solvent vapor dispensing pipe 27, a solvent vaporgenerator 27 a is connected. These solvent vapor dispensing pipes 27 aredisposed such that the solvent vapor is dispensed into the cup 22 from aposition higher than, for instance, the wafer W disposed on thepre-determined position in the cup 22. Further, as shown in FIG. 20, thepipes are disposed in the cup 22 such that the solvent vapor can bedispensed from the both sides of the wafer W.

[0331] Further, at the bottom surface and the cover 21 of the cup 22, asshown in FIG. 19, the solvent nozzles 262 and 263 for dispensing thesolvent, which is a cleaning agent for removing (edge-rinse treatment)the coated film at the circumference portion of the wafer, from thesolvent dispensing source 261, are inserted. The solvent nozzle 263disposed on the cover 21 is to eject the solvent toward thecircumference on the surface side of the wafer W. The solvent nozzle 262disposed on the cup 22 is to remove the coating liquid which goes aroundthe rear surface of the wafer by ejecting the solvent toward thecircumference of the rear surface side of the wafer W.

[0332] Further, to the cup 22, a drain pipe 28, an exhaust pipe 29 areconnected. There is a switching valve 29 a in the mid-way of the exhaustpipe 29.

[0333] Then, the treatment of coating a coating liquid on an wafer Waccording to the method of the third invention will be describedfollowing order. First, the wafer W is carried to the coating unit 2 bythe main arm 13. The carried wafer W is delivered to the chuck 25 at theposition of the dotted line in FIG. 19, for instance. That state isshown in FIG. 21A. Subsequently, after the chuck 25 is lowered, the cup22 is sealed with the cover 21. The coating liquid employed here is onein which colloids or particles of TEOS, which is a metal alkoxide, isdispersed in a solvent containing an organic solvent such as ethyleneglycol and ethyl alcohol and further water and a trace of hydrochloricacid.

[0334] Ethylene glycol is employed to adjust the viscosity to the mostappropriate one for coating the coating liquid.

[0335] Further, other than viscosity adjustment, because of low vaporpressure of ethylene glycol, it can be employed with an object toprevent shrinkage of the film due to volatilization of the solvent inthe aging step from occurring.

[0336] And, in this example, as shown in FIG. 21B, while exhausting fromthe exhaust pipe 29, for instance, vapor of ethylene glycol 260 isdispensed inside the cup 22 from the solvent vapor dispensing pipe 27.Then, after the inside of the cup 22 is filled by the vapor 260, theexhaust is stopped. The solvent vapor 260 inside the cup 22 at this timeis desirable to be the saturated vapor pressure. The reason for this isthat, when the vapor pressure is lower than the saturated vaporpressure, the solvent vaporizes from the coating liquid. On the otherhand, it is because that, when the vapor pressure is higher than thesaturated vapor pressure, that is, when the vapor pressure is in asupersaturated state, the solvent condenses.

[0337] Subsequently, as shown in FIG. 21C, the coating liquid S isdispensed on the center portion of the wafer W from the nozzle 26. Then,as shown in FIG. 22A, by rotating the wafer W with high speed by thechuck 25, the coating liquid is spread over the surface of the wafer Wdue to centrifugal force, to form a coated film. Thereafter, therotation speed is lowered and, as shown in FIG. 22B, the solvent issprayed onto the brim of the wafer W from the nozzles 262 and 263.Thereby, as shown in FIG. 23, the brim portion f of the coated film Fspread over the surface of the wafer W is removed. Thus, due to removalof the coated film at the brim portion of the wafer, since the carryingarm and the coating liquid do not make contact during transfer of thecoated wafer W, the arm is prevented from being contaminated by thecoating liquid. Further, when the wafer W is carried to the carrierafter completion of the process, particles caused to peel from a part ofthe coated film due to groove of the carrier are prevented fromoccurring. Even in this edge rinse-treatment, the inside of the cup 22is being filled by the solvent vapor 260.

[0338] Thereafter, as shown in FIG. 22C, while holding up the cover 21 alittle and letting in air into the cup 22, exhaust from the exhaust pipe29 is carried out. Thus, the inside of the cup 22 is replaced by the airatmosphere. Then, by elevating the cover 21 and the chuck 25, the waferW is delivered to the arm for carrying the wafer from the chuck 25.Thereafter, the wafer is carried to the gelling step.

[0339] The treatment after gelling step will be described briefly. Inthe gelling step, as shown in FIG. 24A, after disposing the wafer W onthe heating plate 71, the cover 72 is put on to form a sealed space.Thus, the wafer W is heated to a temperature of, for instance, 100° C.to expedite the aforementioned gelling. In this case, the saturatedvapor of ethylene glycol is introduced from the gas introducing path 73laid inside the heating plate 71, for instance, and is exhausted fromthe exhaust path 74. Incidentally, this gelling step may be carried outby introducing basic gas such as ammonia gas into the treatment chamber.

[0340] Thereafter, with the identical device as that employed in thecoating treatment for instance, as shown in FIG. 24B, the wafer W isplaced on the spin chuck 75, on the surface thereof, ethanol and HMDS(hexamethyl disilane) are dispensed in this order. Thereby, moisture andOH groups are removed. Subsequently, by dispensing a liquid of lowsurface tension such as heptane, the replacement of the solvent iscarried out. Thereafter, the wafer W is treated in the bake step to forma porous silicon oxide film.

[0341] According to the example 5, by filling the inside of the cup 22by the vapor of ethylene glycol during coating treatment and edge rinsetreatment, the solvent can be suppressed in vaporization from the coatedfilm. As the result, gelling is not hindered, and the pre-determinedthickness can be secured. Incidentally, the edge rinse treatment may becarried out at a different place from the cup 22.

[0342] Here, when the spin coating is carried out as described above, atleast during the wafer W is revolving, the inside of the cup 22 isrequired to be filled with the vapor of the solvent. In that case, thenozzle can be disposed different from the cup 22, for instance. Then,after the coating liquid is dripped on the wafer W from the nozzle, thecover is closed and the solvent vapor is dispensed into the cup 22. Thisis also included in the third invention.

[0343] Incidentally, in order to dispense into the cup 22 by switchingthe vapor of the solvent and the atmosphere, as shown in FIG. 25, at themidway of the solvent vapor dispensing pipe 27, a 3-way valve 264 oneend thereof is open to the atmosphere may be disposed. Thereby, byswitching the 3-way valve 264 toward the flow side of the atmosphere,while introducing the atmosphere into the cup 22 after coating, theinside of the cup 22 can be exhausted. By connecting the aforementionedone end of the 3-way valve 264 to a nitrogen gas source, nitrogen gascan be dispensed instead of the atmosphere.

[0344] In the third invention described above, the solvent vapordispensing pipe 27 can be disposed such that the vapor of the solventcan be dispensed into the cup 22 from 3 or more directions, forinstance. Further, by employing an open end cup and by surrounding it byan air tight vessel, the inside thereof is made an atmosphere of thevapor of the solvent and coating may be carried out therein. Further,the edge rinse treatment can be carried out in the open atmosphere, andthe coating can be carried out with a method other than the spin coat.Further, as the substrate to be treated, without restricting to thewafer, glass substrates for liquid crystal displays may be employed.

[0345] As described above, according to the third invention, since thecoating liquid in which colloids or particles of the starting substancesof the film component are dispersed in the solvent can be coated on thesubstrate while preventing the solvent from evaporating, the excellentthin film such as the interlayer insulating film can be obtained.

[0346] Further, since the coated film at the brim portion of thesubstrate is removed in the atmosphere of the vapor of the solvent,vaporization of the solvent of the coating liquid can be suppressedfurther more.

EXAMPLE 6

[0347] Next, example 6 involving the fourth invention will be described.

[0348]FIG. 26 is a side view of a profile of the coating unit 2involving example 6.

[0349] In the figure, reference numeral 331 denotes a chuck holding anwafer W in level (includes a state which is approximately level). Thischuck 331 is composed of a vacuum chuck, for instance, and is designedto suck and hold the rear surface side of the wafer W. At theapproximate center of the bottom surface of the chuck 331, a rotationaxis 333 capable of going up and down and rotating by a driving portion332 is attached. Thereby, the chuck 331 is going up and down between adelivering position of the wafer W above the cup which is shown in thefigure by the dotted line and will be described later and a treatmentposition of the wafer W shown in the figure by the solid line. Further,the chuck 331 is capable of revolving around a vertical axis.

[0350] In the circumference of the chuck 331 and the wafer W which arein the treatment position, a cup 340 is disposed to surround these. Onthe upper surface of the cup 340, an opening 341 through which the waferW is passable is formed. This opening 341 is opened or closed by a cover342 disposed so as to be capable of going up and down. Further, on theside wall portion of the cup 340, a solvent vapor dispensing pipe 351for dispensing the vapor of the solvent component such as ethyleneglycol, which is employed in the coating liquid X and will be describedlater, into the cup 340 is connected. Further, the vapor of ethyleneglycol is generated at the solvent vapor source 352. Further, at thebottom of the cup 340, a drain pipe 353 and an exhaust pipe 354 areconnected.

[0351] At the cover 342, a coating liquid nozzle 361 for dispensing thecoating liquid X approximately on the rotation center of the surface ofthe wafer (the surface thereon the coated film is formed) and a coatingliquid nozzle 362 for dispensing the solution S approximately on therotation center of the surface of the wafer are disposed. These nozzles361 and 362 are attached slanted combined with the cover 342 such thatthe respective tip end directs toward the approximate center of rotationon the surface of the wafer.

[0352] Now, the coating liquid X will be described. In this coatingliquid X, colloids or particles of a metal alkoxide such as TEOS whichis a starting component are dispersed in a solvent, and, for thesolvent, ethylene glycol, ethyl alcohol, water and a trace ofhydrochloric acid are employed. An example of the ratio of therespective components in the coating liquid is as follows. For instance,TEOS and water are employed in an equal molar ratio, and ethylene glycolsolution and ethanol solution are employed in several times of water bythe molar ratio.

[0353] Further, the solution S dispensed on the surface of the waferfrom the solution nozzle 62 is preferable to be a solution of smallerviscosity than that of the component of the highest viscosity in thecomponents of the solvent of the coating liquid X, and to be capable ofdissolving the metal alkoxide and water. Here, the component of thehighest viscosity of the components of the solvent of the coating liquidX is ethylene glycol. Further, it is known that the metal alkoxide suchas TEOS or the like is generally insoluble in water, whereas is solublein alcohol and organic solvent. Therefore, as the solution S capable ofbeing employed in the present example 6, alcohol or organic solvent ofsmaller viscosity than ethylene glycol can be employed. Among them,ethanol, one of components of the solvent of the coating liquid X, isparticularly desirable to be employed.

[0354] Subsequently, a method involving the fourth invention beingcarried out at the aforementioned apparatus of forming a film will bedescribed.

[0355] In this apparatus of forming a film, the wafer W, after beingsubjected to hydrophobic treatment and cooling treatment, issequentially carried to a coating unit 2, an aging unit 3, and a solventreplacement unit 4 by a main arm 13, and, after the respectivepredetermined treatments are carried out at these units, is subjected tobake treatment.

[0356] Now, steps of forming a film being carried out in the coatingunit 2 will be described with reference to FIG. 26 and FIG. 27A throughFIG. 27D. First, the cover 342 is elevated up to the position of thedotted line in FIG. 26. At the same time, the chuck 331 is elevated upto a position above the cup 340. Then, at the position of the dottedline in FIG. 26, the wafer W carried to the unit 2 by the main arm 13 isdelivered to the chuck 331. Then, the chuck 331 is lowered to thetreatment position, and the cover 342 is lowered to seal the cup 340.

[0357] And, in this example, while exhausting from the exhaust pipe 354for instance, ethylene glycol vapor is dispensed into the cup 340 fromthe solvent dispensing pipe 351. Then, after the inside of the cup 340is filled by the vapor, exhaust is stopped. Then, as shown in FIG. 27A,the solution S such as 99.9% ethanol solution for instance is dispensedat the approximate center of rotation of the wafer W from the solutionnozzle 362. Then, as shown in FIG. 27B, the wafer W is rotated by thechuck 331. Thereby, the solution S is diffused over the whole surface ofthe wafer W due to centrifugal force, to spread.

[0358] Subsequently, as shown in FIG. 27C, the coating liquid X isdispensed on the approximate rotation center of the wafer W from thecoating liquid nozzle 361. In this case, the coating liquid X ispreferable to be dispensed when the coated solution S is in a statewhere it does not vaporize and exists on the surface of the wafer W.

[0359] Then, as shown in FIG. 27D, the wafer W is rotated by the chuck331, the coating liquid X is diffused and spread over the whole surfaceof the wafer due to centrifugal force, to form the coated film.

[0360] Incidentally, though not shown in the figure, thereafter, thinneris sprayed on the brim portion of the wafer W from a thinner nozzle inthe cup 340, thereby the coated film of the brim portion is removed.

[0361] Further, in this example, why the inside of the cup 340 is filledby the vapor of ethylene glycol is to suppress vaporization of thesolvent in the coating liquid.

[0362] Thereafter, while maintaining a state where the cover 342 isbeing held up a little, the inside of the cup 340 is evacuated. Then, byelevating the cover 342 and the chuck 331, the wafer W is delivered tothe carrying arm 13 from the chuck 331, and is sequentially transferredto the aging unit 3 and the solvent replacement unit 4. At therespective units 3 and 4, the gelling step and the solvent replacementstep are carried out. Then, these steps will be described briefly withreference to FIG. 28A and FIG. 28B.

[0363] First, in the gelling step, the treatment of gelling the colloidsof TEOS contained in the coated film on the wafer W is carried out tolink the colloids in a reticular structure. For this, in a treatmentchamber 371 filled by the vapor of ethylene glycol, the wafer W isheated to around 100° C. by the heating plate (FIG. 28A). Here, why thevapor of ethylene glycol is introduced into the treatment chamber 371 isto suppress vaporization of the solvent in the coated film. Therefore,at the temperature of, for instance, the inside of the treatment chamber371, vapor is adjusted to be 100%. In this gelling step, instead ofheating, a catalyst such as ammonia can be employed.

[0364] In that case, in the treatment chamber 371 filled by an ammoniagas, for instance, treatment is carried out at normal temperature, thegelling of the colloids of TEOS may be expedited by the ammonia gaswhich is a basic catalyst.

[0365] Subsequently, in the solvent replacement step, by dispensingsequentially ethanol, HMDS (hexamethyl disilane) and heptane on theapproximate rotation center of the surface of the wafer W, the solventin the coated film is replaced by another solvent. Therefore, in thesolvent replacement unit 4, as shown in FIG. 28B, the wafer W is held inlevel on the wafer hold 372 constituted to be capable of rotating aroundthe vertical axis. On the other hand, 3 pieces of nozzles 373 (373 a,373 b, 373 c) respectively ejecting ethanol, HMDS, and heptane areprepared. Then, these nozzles 373 (373 a, 373 b, 373 c), by grasping bythe carrying arm 374 and pulling out in turn from the respective nozzlereceivers which are not shown in the figure, are transferred to thecenter portion of the wafer W.

[0366] In this step, first, the wafer W is rotated. In this state,ethanol is dripped on the approximate rotation center of the surface ofthe wafer W to diffuse over the whole surface of the wafer W due tocentrifugal force.

[0367] Thereby, ethanol dissolves in the moisture in the coated film. Asthe result, the moisture is replaced by ethanol. Subsequently, whilerotating the wafer W similarly, HMDS is dripped on the surface of thewafer W. Thereby, OH groups in the coated film are removed. Further,heptane is dispensed on the surface of the wafer W. Thereby, the solventin the coated film is replaced by heptane. The reason why to employheptane is that, due to use of a solvent of low surface tension, theforce on a porous structure that is a reticular structure of TEOS can bemade small, and the reticular structure of TEOS is made not to collapse.

[0368] The wafer W thereon the predetermined treatment is carried out atthe solvent replacement unit 4 is transferred to the bake unit by themain arm 13. At this unit, the wafer W is subjected to the baketreatment. Thereby, on the surface of the wafer W, an interlayerinsulating film consisting of a silicon oxide film is formed.

[0369] According to the aforementioned example 6, in the step of forminga film, prior to coating of the coating liquid, the whole surface of thewafer is coated by ethanol. In a state where the ethanol exists on thesurface of the wafer W, thereon the coating liquid X is dispensed. Here,since the ethanol is lower in viscosity than ethylene glycol, theethanol itself readily diffuses over the whole surface of the wafer.Therefore, the ethanol goes into minute concave/convex portions formedon the surface of the wafer W thoroughly.

[0370] Thus, in a state where ethanol exists on the whole surface of thewafer, on the surface of the wafer W, the coating liquid X is dispensed,to diffuse. The components composing the coating liquid X, that is, allof TEOS, water, ethylene glycol and hydrochloric acid are soluble inethanol. Therefore, the coating liquid X mingles with ethanol on thesurface of the wafer W. As the result, the coating liquid X becomes astate of capable of being mingled with ethanol, thereby goes into theplaces where ethanol exists.

[0371] Moreover, ethanol is lower in viscosity than ethylene glycol asmentioned above. Therefore, the coating liquid X mingled with ethanolbecomes low in viscosity and becomes readily diffused. Therefore, whenthe wafer W is rotated, the coating liquid X spreads universally on thewhole surface of the wafer and goes into the minute concave/convexportions. Therefore, all over the surface of the wafer, the coated filmis formed.

[0372] In this time, even when, as the coating liquid S, the solution oralcohol which is lower in viscosity than ethylene glycol and dissolvesmetal alkoxide and water is employed, the component of the coatingliquid X and the solution S mingle each other. As the result, theviscosity of the coating liquid X to be spread over the surface of thewafer W becomes low, thereby the similar effect as ethylene glycol canbe obtained.

[0373] Further, when, as the solution S, ethanol which is one of solventcomponents of the coating liquid X is employed, since ethanol isincluded as the solvent in advance, mingling of the solution S and thecoating liquid S on the surface of the wafer is proceeded readily.Therefore, during mingling of the solution S and the coating liquid X,there are no generation of bubbles and no remaining thereof in thecoated film. Therefore, a coated film of more excellent quality can beformed.

[0374] Now, if a solution of higher viscosity than ethylene glycol hadbeen employed, the solution S itself would be difficult to diffuse.Therefore, penetration into the minute concave/convex portions on thesurface of the wafer W becomes difficult. Further, since the viscosityof the coating liquid X after the solution S and the coating liquid Xwere mingled becomes high, the coating liquid X becomes further moredifficult to diffuse. As the result, an even coating of the coatingliquid X on the whole surface of the wafer W becomes difficult.

[0375] Further, if a solution in which a metal alkoxide or water doesnot dissolve is employed as the solution S, the solution S and thecoating liquid X do not mingle. Therefore, the viscosity of the coatingliquid X can not be made low. Furthermore, because of hindrance of thesolution S to the coating liquid X, coating on the surface of the waferW can not be carried out. Incidentally, inclusion of water in thesolvent of the coating liquid is not restricted. However, when water iscontained, the solution is necessary to be capable of dissolving thestarting substance and water.

[0376] Thus, according to the aforementioned example 6, a coating liquidX becomes capable of being coated easily on the surface of the wafer W,thereby the coating liquid X can be coated on the whole surface of thewafer W universally. Therefore, since formation of the film can besecured all over the whole surface, as the result, a thin film ofexcellent quality such as an interlayer insulating film can be formed.

[0377] In the above-mentioned method of forming a film of the fourthinvention, the aforementioned solvent replacement step is not alwaysnecessary. By carrying out gelling step after the step of forming afilm, a thin film such as an interlayer insulating film may be formed.

[0378] According to the fourth invention, before coating a coatingliquid in which particles or colloids of a starting substance of a filmcomponent are dispersed in a solvent, a solution of which viscosity issmaller than that of the component of the highest viscosity amongsolvents of the coating liquid and is capable of dissolving the startingsubstance is coated on the surface of the substrate. Thereby, coating ofthe coating liquid on the surface of the substrate becomes easy, therebythe film can be universally formed over the whole surface of thesubstrate. As the result, an excellent thin film such as an interlayerinsulating film can be obtained.

EXAMPLE 7

[0379] Next, example 7 involving the fifth invention of the presentapplication will be described.

[0380]FIG. 1 is a plan view showing an apparatus involving example 7.

[0381]FIG. 2A through FIG. 2D are diagrams showing schematically eachstep of the method of forming a film involving example 7.

[0382] In this apparatus, an wafer W, after being subjected tohydrophobic treatment and cooling treatment, is sequentially transferredto a coating unit 2, an aging unit 3, and a solvent replacement unit 4by a main arm 13, and at these units, the predetermined treatments arecarried out, respectively.

[0383] That is, at the unit 2, as shown in FIG. 2A, on the approximaterotation center of the surface of the wafer W sucked and held by anwafer holder 21 which will be described later, by the later describedcoating liquid nozzle 5, a coating liquid X is dispensed. Then, as shownin FIG. 2B, by rotating the wafer W, the coating liquid X is spread overthe whole surface of the wafer W due to centrifugal force to form a film(treatment of forming a film).

[0384] Then, at the aging unit 3, colloids of TEOS contained in thecoated film on the wafer W is gelled, treatment thereby to link thecolloids to form a reticular structure is carried out (gellingtreatment). To carry out this gelling, in a treatment chamber 37 filledby ethylene glycol vapor, the wafer W is heated to approximately 100° C.by a heating plate (FIG. 2C). In this step, instead of heating, in thetreatment chamber 37 filled by an ammonia gas, treatment is carried outat the normal temperature, thereby gelling of the colloids of TEOS maybe enhanced by the ammonia gas which is a basic catalyst. Incidentally,the reason why the inside of the treatment chamber 37 is filled by theethylene glycol vapor is to suppress vaporization of the solvent in thecoating liquid.

[0385] Subsequently, at the solvent replacement unit 4, on theapproximate rotation center of the surface of the coated film M on thewafer W, ethanol, HMDS (hexamethyl disilane) and heptane are dispensedin turn, thereby the solvents in the coated film M are replaced by othersolvents (solvent replacement treatment). For this, at the solventreplacement unit 4, as shown in FIG. 2D, the wafer W is held in level byan wafer holder 21 constituted to be capable of rotating around avertical axis. In this state, first, ethanol is dripped on theapproximate rotation center of the surface of the wafer W, thereafterthe wafer W is rotated to make diffuse ethanol on the whole surface ofthe wafer due to centrifugal force. Thereby, ethanol dissolves intomoisture in the coated film M, resulting in replacement of the moistureby ethanol.

[0386] Subsequently, in the similar manner, by dispensing HMDS on thesurface of the wafer W, OH groups in the coated film are removed. Then,by dispensing heptane on the surface of the wafer W, the solvent in thecoated film is replaced by heptane. The reason why heptane is employedis that, due to use of a solvent of smaller surface tension, the forceput on the porous structure, that is, a reticular structure of TEOS, isreduced, thereby the reticular structure of TEOS is prevented fromcollapsing.

[0387] The wafer W thus carried out the predetermined treatment at thesolvent replacement unit 4 is transferred to a bake unit by the main arm13. The wafer W is bake treated at this unit, thereby an interlayerinsulating film consisting of a silicon oxide film is formed on thesurface of the wafer W.

[0388] The method of forming a film of the fifth invention ischaracterized in formation treatment of a film.

[0389] In the following, the coating unit 2 where this treatment iscarried out will be described with reference to the side view of theprofile of FIG. 29. Reference numeral 431 in the figure denotes a chuckfor holding an wafer W level (includes approximately level). This chuck431 is constituted of a vacuum chuck for instance, the rear side of thewafer W is sucked and held. On the approximate center of the bottomsurface of the chuck 431, a rotation axis 433 capable of going up anddown and rotating by a driving portion 432 is attached. With such astructure, the chuck 431 is capable of going up and down between adelivering position of the wafer W above the fixed cup which will bedescribed later and a treatment position of the wafer W shown by thesolid line in FIG. 29, and is capable of rotating around the verticalaxis.

[0390] In the circumference of the chuck 431 and the wafer W which arepositioned at the treatment position, a fixed cup 440 is disposed inorder to surround them. On the upper surface of the fixed cup 440, anopening 441 where the wafer W is passable is formed. The opening portion441 is opened and closed by a cover 442 disposed to be capable of goingup and down. Further, on the bottom surface of the fixed cup 440, adraining pipe 443 and an exhaust pipe 444 are connected.

[0391] Above the wafer W which is in a treatment position, a coatingliquid nozzle 450 is attached to dispense the coating liquid which willbe described later on the approximate center of the surface of the waferW (the surface where a coated film is formed). This coating liquidnozzle 450 is attached to a supporting arm 451 such that the tip endthereof is directed toward the approximate rotation center of thesurface of the wafer. The supporting arm 451 is constituted to becapable of moving in a level direction by a driving portion 452. As theresult, the coating liquid nozzle 450 is capable of moving between adispensing position (a position shown in FIG. 29) of dispensing acoating liquid on the surface of the wafer, and a nozzle cleaningportion 453 disposed outside the wafer W which is in the treatmentposition. The nozzle cleaning portion 453 is a portion which receivesthe liquid overflowing from the coating liquid nozzle 450 and isconstituted such that, a liquid exhaust path 453 b is connected to thebottom surface of a cylindrical liquid receiver 453 a, for instance.

[0392] The coating liquid nozzle 450 is connected to one end side of asolvent dispensing pipe 461 for dispensing a coating liquid X to thenozzle 450. The other end side of the coating liquid dispensing pipe 461is connected to a mixing portion 462. This coating liquid dispensingpipe 461 has a jacketed structure having an internal pipe and anexternal pipe for instance. Through the external pipe, temperaturecontrolling liquid is flowed.

[0393] To the mixing portion 462, a plurality, for instance, 2, ofreserving tanks 463 and 464 for reserving respectively the first liquidand the second liquid which are components of the coating liquid X areconnected through solvent dispensing pipes 463 a and 463 b having pumpsP1 and P2. The respective liquids reserved in these first and secondreserving tanks 463, 464 are mixed at the mixing portion 462, and aredispensed to the coating liquid nozzle 450 through the coating liquiddispensing pipe 461.

[0394] Here, the coating liquid X will be described. In this coatingliquid X, colloids or particles of a metal alkoxide such as TEOS whichis a starting substance of a film component are dispersed in a solvent.As a solvent, ethanol solution, ethylene glycol, water and a trace ofhydrochloric acid (HCl) can be employed.

[0395] In such a coating liquid X, the colloids or particles of TEOS areinsoluble or difficult to be dissolved in water. The liquid in which thecolloids or particles of the TEOS, ethylene glycol, water andhydrochloric acid are mixed is reserved in the first reserving tank 463as the first liquid S1. Further, an ethanol solution is an organicsolvent which dissolves water and the colloids and the like of TEOS, andis reserved in the second reserving tank 464 as the second liquid S2.

[0396] Next, the formation treatment of a film which is carried out atthe coating unit 2 will be described with reference to FIG. 30A throughFIG. 30D. First, a cover 442 is elevated up to the position shown by thedotted line in FIG. 29. At the same time, a chuck 431 is elevated up tothe position above the fixed cup 440. In this state, at the position ofthe dotted line in FIG. 29, the wafer W transferred to the unit 3 by themain arm 13 is delivered onto the chuck 431. Then, the chuck 431 islowered to the treatment position, and the cover 442 is lowered to sealthe fixed cup 440.

[0397] And, first, as shown in FIG. 30A, the coating liquid X isdispensed on the approximate rotation center on the surface of the waferW from the coating liquid nozzle 450 to form a coated film on thesurface. That is, the coating liquid X (mixed liquid) is made by mixingthe first liquid S1 and the second liquid S2 at the mixing portion 462,then this coating liquid X is dispensed on the surface of the wafer Wwithin 6 min. after mixing of the respective liquids to coat.

[0398] In specific, by operating pumps P1 and P2, the predeterminedamounts of the first liquid S1 and the second liquid S2 are dispensed tothe mixing portion 462 from the first reserving and the second reservingtanks 463 and 464. At the mixing portion 462, these first and the secondliquids S1 and S2 are mixed to prepare the coating liquid X, then thecoating liquid X is dispensed on the surface of the wafer W through thecoating liquid dispensing pipe 461. Then, by rotating the wafer W, thecoating liquid X is diffused and spread over the whole surface of thewafer due to centrifugal force to form a coated film. Thus, bydispensing the coating liquid X on the surface of the wafers W within 6min. after the first and the second liquids S1 and S2 are mixed, thepredetermined number of the wafers W undergoes film formation.

[0399] Incidentally, after films are formed, a thinner is sprayed on thebrim portion of the wafer W from a thinner nozzle in the fixed cup 440not shown in the figure to remove the coated film of the brim portion.Thereafter, the cover 442 and the chuck 431 are elevated to deliver thewafer W from the chuck 431 to the carrying arm 13, then it is carried tothe aging unit 3 and the solvent replacement unit 4 in turn.

[0400] Subsequently, at the coating unit 2, before coating the coatingliquid X on the surface of the following wafer W, as shown in FIG. 30B,the inside of the path of the coating liquid X composed of the mixingportion 462 and the coating liquid pipe 461 is cleaned by an organicsolvent. That is, after the coating liquid nozzle 450 is moved above thenozzle cleaning portion 453, supply of the first liquid to the mixingportion 462 is stopped. Then, only the second liquid is dispensed to thecoating liquid dispensing pipe 461 through the mixing portion 462.

[0401] By carrying out like this, the flow path of the coating liquid Xis replaced gradually from the upstream side by an organic solvent, theethanol solution S2 in this example (FIG. 30B), before long, iscompletely replaced by the ethanol solution S2 (FIG. 30C). Thereby, theinside of the flow path is cleaned by the ethanol solution S2. In thistime, the coating liquid X and the ethanol solution S2 flowing out ofthe coating liquid nozzle 450 are exhausted from the liquid exhaust path453 b through the liquid receiver 453 a. Here, as an organic solvent forcleaning the flow path, it is preferable to employ a component whichdissolves the starting substance of the film component and water. Assuch organic solvents, alcohol such as an ethanol solution, IPA(isopropyl alcohol) or the like can be employed.

[0402] After thus replacing the inside of the flow path by the ethanolsolution S2, as shown in FIG. 30C and FIG. 30D, the first and the secondliquids S1 and S2 are dispensed into the inside of the flow path. Thus,by replacing the inside of the flow path by the coating liquid X, then,by moving the coating liquid nozzle 450 to the dispensing position, thewafer W is again subjected to the formation treatment of the coatedfilm. This time, after the coating liquid nozzle 450 is moved to thedispensing position, the inside of the flow path may be replaced by thecoating liquid X, or, on the surface of the wafer W, the ethanolsolution and the coating liquid X may be replaced.

[0403] According to the aforementioned example 7, since the coatingliquid X of within the film quality deteriorating time period aftercompletion of mixing of the first and the second liquids S1, S2, forinstance, within 6 min. after completion of mixing is coated on thesurface of the wafer W, as obvious from the experimental results whichwill be described later, deterioration of the film quality of coatedfilm can be suppressed.

[0404] Here, the experiments which the inventors carried out are asfollows. That is, the aforementioned first liquid S1 and the secondliquid S2 are mixed to form the coating liquid X. Then, by varying thetime periods up to dispensing the coating liquid X on the surface of thewafers W after mixing, the coated films are formed on the surfaces ofthe wafers W by the aforementioned method. Then, the state of suchformed coated films are observed by visual observation.

[0405] This time, the inventors had grasped from experience that thefilm quality of the films to be formed deteriorated when the time periodup to dispensing on the surface of the wafer W passed approximately 6min. after the first liquid S1 and the second liquid S2 are mixed.Therefore, in order to confirm the critical point, the experiment wascarried out by varying the time periods up to dispensing on the surfaceof the wafers W such as 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 10min, and 30 min, respectively after mixing.

[0406] As to the coated films obtained under the respective conditions,the in-plane uniformity of the film thickness=(standard deviation offilm thickness in the wafer plane)/(average film thickness in the waferplane)×100(%) is obtained. On the other hand, the obtained coated filmsare checked by visual observation. The results are shown in FIG. 31.Here, ∘ denotes a state where no irregularity is observed in the coatedfilm, and × denotes a state where a radial truck is seen on the surfacelike a running truck of a particle. From these results, it is confirmedthat, by employing the coating liquid X of within 6 min after the firstand the second liquids S1 and S2 are mixed, deterioration of the filmquality and in-plane non-uniformity of the film thickness of the formedfilm can be suppressed.

[0407] Thus, when the coating liquid X which elapsed more than 5 min.after mixing of the TEOS and the solvent such as ethanol solution or thelike is employed, fluctuation of the film thickness or film quality ofthe coated film occurs, though the mechanism being not clarified, theinventors assume as follows. That is, the coating liquid X is a mixtureof the TEOS and the solvent. When the TEOS and the solvent are mixed,hydrolysis and polymerization of the TEOS occur. When a certain timeperiod elapsed after mixing, the colloids grow too much and deviate fromthe appropriate colloidal state to obtain the best film quality. As theresult, fluctuation in the thickness or the film quality of the coatedfilm are considered to occur.

[0408] Here, whereas TEOS is difficult to dissolve in water but it issoluble in alcohol, accordingly the hydrolysis or the polymerization ofTEOS is construed to occur after elapse of a certain time period afterdissolution of the TEOS, water and hydrochloric acid into the ethanolsolution. It is considered that it occurs when the time period of morethan 6 min. had elapsed after the ethanol solution and the othercomponents were mixed, for instance.

[0409] Therefore, like example 7, by separating the components of thecoating liquid X into an ethanol solution (the second liquid) and theother components (the first liquid), and by forming the film whileemploying the coating liquid X of within 6 min. after mixing of these,the coating liquid X can be employed before the colloids grow too much.As the result, it is considered that deterioration of the film qualityof the coated film can be suppressed.

[0410] Further, as in example 7, after forming films on thepredetermined pieces of wafers W with a coating liquid X of within 5min. after mixing of the first and the second liquids S1, S2, beforecoating the coating liquid X on the next wafer W, the mixing portion 462and the flow path of the down stream side of the mixing portion 462 arecleaned. Thereby, in the flow path, there does not remain the oldcoating liquid which elapsed more than 5 min. after mixing. Therefore,when the subsequent wafer W is processed, there is no chance of the oldcoating liquid X being dispensed on the wafer W, accordingly the filmquality of the coated film is prevented from deteriorating.

[0411] Further, if alcohol such as an ethanol solution or the like isemployed as the organic solvent in this case, as mentioned above, TEOS,water, and hydrochloric acid dissolve in the ethanol solution.Therefore, since the respective components of the coating liquid Xexisting in the flow path are dissolved in the ethanol solution,cleaning of the flow path can be readily carried out. Further, likeexample 7, by transferring the first and the second liquids S1, S2respectively from the separate reserving tanks 463, 464 into the mixingportion 462 by pumps P1, P2, the mixing ratio of the first and thesecond liquids S1, S2 can be advantageously varied with ease.

[0412] Thus, according to the example 7, since the hydrolysis andpolymerization of the coating liquid X dispensed on the surface of thewafer W can be suppressed, deterioration of the film quality of thecoated film due to decomposition of the coating liquid X can besuppressed. As the result, excellent thin films such as interlayerinsulating films can be formed.

[0413] In the above described example 7, instead of disposition of thefirst and the second reserving tanks 463, 464 or the mixing portion 462,on another place the first and the second liquids S1, S2 are mixed.Then, within 6 min. after the preparation of the mixed liquid (coatingliquid X), the coating liquid may be coated on the surface of the waferW. Further, vapor of ethylene glycol is dispensed inside the fixed cup440, after the inside of the cup 440 is filled by the vapor, the coatingliquid X may be dispensed. In this case, there is an effect thatvaporization of the solvent of the coating liquid X can be suppressed.

[0414] In the aforementioned method of forming films of the fifthinvention, the replacement treatment of the aforementioned solvent isnot necessarily required. That is, by carrying out gelling treatmentafter formation of a coated film, a thin film such as an interlayerinsulating film may be formed.

[0415] According to the fifth invention, the first liquid containingparticles or colloids of a starting material of a film component andwater and the second liquid consisting of an organic solvent capable ofdissolving water and the film component are mixed, the mixture of theliquids is coated on the surface of the substrate within 6 min. afterpreparation to form a coated film. Thereby, deterioration of the filmquality can be suppressed. As the result, an excellent thin film such asan interlayer insulating film can be obtained.

[0416] Incidentally, in the example 7, based on empirical facts orexperiments, the film quality deterioration time period is set at 6min., however, the film quality deterioration time period variesdepending on chemicals or solvents to be employed, treatment conditionsor the like.

[0417] Therefore, in the case of the conditions being different from theexample 7, the appropriate value of the film quality deterioration timeperiod is determined each time by experiment or the like. Thus,corresponding to the respective conditions, the film qualitydeterioration time periods are determined. Therefore, in the fifthinvention, the film quality deterioration time period is not restrictedto 6 min.

EXAMPLE 8

[0418] Next, example 8 involving the sixth invention of the presentapplication will be described.

[0419]FIG. 1 is a plan view showing an apparatus involving Example 8.

[0420]FIG. 2A through FIG. 2D are diagrams showing schematically therespective steps of a method of forming a film involving example 8.

[0421] In FIG. 2A through FIG. 2D, the flow of treatment of forming afilm is schematically shown in order. An wafer W prior to the treatmentand taken out by a main arm 13 from the inside of a cassette C of acassette stage CS is accommodated in a coating unit 2. Then, in a statewhere the inside of the coating unit 2 is filled by a vapor of solvent,a coating liquid T is dripped on the surface of the wafer W (cf. FIG.2A). The coating liquid employed here is one in which colloids orparticles of TEOS which is a metal alkoxide are dispersed in a solventcontaining organic solvents such as ethylene glycol and ethyl alcoholand further containing water and a trace of hydrochloric acid. Becauseof low vapor pressure of ethylene glycol, it remains in the film as thesolvent even after vaporization of ethyl alcohol, to work forsuppressing shrinkage of the film.

[0422] Subsequently, when the wafer W is rotated with high speed in astate where the inside of the coating unit 2 is filled by the vapor ofthe solvent, the coating liquid in which sol of TEOS is dispersed in thesolvent is spread over the surface of the wafer W to form a film F(FIG.2B).

[0423] Next, the wafer W is placed on the stage 31 of the aging unit 3and is sealed by the cover 33. Then, under normal temperature, into theaging unit 3, a treatment gas for enhancing gelling of the coated filmis introduced to gel the film (FIG. 2C). The treatment gas is an ammoniagas including water vapor.

[0424] Subsequently, in the solvent replacement unit 4, with ethylalcohol, HMDS (hexamethyl disilane) and heptane, solvent replacement ofthe gelled film is carried out (FIG. 2D). Thereby, moisture in thecoated film is replaced by ethyl alcohol. Further, OH groups in thecoated film are removed by HMDS. Further, the solvent in the coated filmis replaced by heptane. Incidentally, the reason why heptane is employedis to prevent the reticular structure of TEOS from collapsing bydecreasing the force put on the porous structure, that is, the reticularstructure of TEOS through employment of solvent of small surfacetension. Thereafter, the wafer W is treated at the bake unit for 1 min.,for instance. Thus, on the surface of the wafer W, an interlayerinsulating film consisting of a silicon oxide film is formed.

[0425]FIG. 32 is a diagram diagrammatically showing one example of theaforementioned aging unit 3. As shown in FIG. 32, this aging unit 3comprises a stage 561 thereon the wafer W is placed, a cover 563 sealingthe space above the stage 561 together with it, and an exhaust path 565having an opening in the center portion of the cover 563.

[0426] The cover 563 is intimately connected to the circumferenceportion of the stage 561 through a sealing member 562, and constitutesthe treatment chamber 560 together with the stage 561.

[0427] And, along the outside of the brim of the wafer W placed on thestage 561, a plurality of or slit like gas intakes 564 are opened.Further, on the bottom surface of the aging unit 3, 3 pieces, forinstance, of pins 567 capable of going up and down are disposed to becapable of freely appearing and disappearing. These pins 567 capable ofgoing up and down are driven up and down between the stage 561 and theabove position thereof by a driving source 566 for going up and down thewafer W.

[0428] The gas intake 564 a is connected to a treatment gas dispensingpipe 581. This dispensing pipe 581 is branched at the midway, thebranched pipes are connected to the first gas generating source 571 andthe second gas generating source 572 through switching valves V1 and V2,respectively. The first gas generating source 571 and the second gasgenerating source 572 are constituted in the identical manner.

[0429] These first gas generating source 571 and second gas generatingsource 572 comprise a tank 574 a reserving commercial ammonia water(NH₄OH) (ammonia concentration: 30% by weight at normal temperature)573, a bubbling gas feeding pipe 575 for carrying out bubbling byintroducing an ammonia gas into the ammonia water 573 in the tank 574 b,an exhaust takeout 576 exhausting the treatment gas generated bybubbling, and a means 577 for maintaining the temperature of the ammoniawater 573 at a constant temperature for instance at the normaltemperature. Incidentally, the tanks 574 a, 574 b correspondsrespectively to the first chamber and the second chamber in claim 37.

[0430] The means for keeping a constant temperature is not restricted inparticular. As shown schematically in FIG. 32, for instance, the tank574 can be constituted by winding spiral a pipe 578 which is acirculating path of water. In this case, the pipe 578 is connected to acirculating device of water not shown in the figure and water adjustedto the normal temperature is flowed all the time. Thereby, thetemperature of the ammonia water 573 reserved in the tank 574 is alwaysmaintained at the normal temperature.

[0431] The treatment gas feeding pipe 581 is branched, between the firstgas generating source 571 and the valve V1, and between the second gasgenerating source 572 and the valve V2, respectively, into bypasses 582,583 proceeding to the exhaust paths through switching valves V3, V4.

[0432] Next, operation of the aging unit 6 of the aforementionedconfiguration will be described. The ammonia water in the first and thesecond gas generating sources 571, 572 is maintained at the normaltemperature in advance by circulating the temperature controlled water.Now, in the first gas generating source 571, bubbling of ammonia gas isbeing carried out and the ammonia gas 573 of the first gas generatingsource 571 has already reached the saturated concentration of ammonia(approximately 33% by weight). Thereby, the treatment gas consisting ofammonia gas containing water vapor (considered to be in a nearlysaturated state) is generated and is exhausted through valve V3. Duringthis, the switching valve V2 on the second gas generating source 572side is closed.

[0433] Then, the wafer W is carried into the treatment chamber 560 fromthe coating unit 2, thereafter treatment is carried out for thepredetermined time period. During the treatment, the switching valve V1on the first gas generating source 571 side is opened, and the valve V3to the exhaust side is closed, and the treatment gas is dispensed fromthe first gas generating source 571 to the inside of the treatmentchamber 560 (the first treatment step).

[0434] In the case of the ammonia water in the first gas generatingsource 571 decreasing and the ammonia water being replenished thereto,by letting start bubbling of the ammonia gas in advance at apredetermined timing even at the second gas generating source 572, theammonia water 573 is made to reach the saturated concentration ofammonia and to generate ammonia gas containing water vapor. During this,on the second gas generating source side 572, the switching valve V2 iskept closed, and by opening the valve V4 to the exhaust side, thegenerated gas is released directly to the exhaust path through thebypass 583 from the second gas generating source 572 (preparatoryexhaust step).

[0435] In this state, the valve V1 which is on the first gas generatingsource 571 side and was being opened is closed to stop feeding of thetreatment gas to the treatment chamber 560 from the first gas generatingsource 571. At the same time, the valve V2 which is on the second gasgenerating source 572 side and was being closed is opened to feed thetreatment gas to the treatment chamber 560 from the second gasgenerating source 572. In this time, at the same time with switching ofvalves V1, V2, the valve V3 which is on the first gas generating source571 side and was being closed is opened. Thereby, the gas generated atthe first gas generating source 571 is made to be released to theexhaust path. At the same time with this, the valve V4 which is on thesecond gas generating source 572 side and was being opened is closed(the second treatment step).

[0436] Thereafter, the ammonia water is replenished to the first gasgenerating source 571 to let generate the ammonia gas containing watervapor from the ammonia water which reached the saturated concentrationof ammonia by bubbling of ammonia gas. On the other hand, in the case ofthe ammonia water in the second gas generating source 572 decreasing andthe ammonia water being replenished thereto, by letting bubbling goingon at the first gas generating source 571, similarly the treatment gasfeeder is again switched from the second gas generating source 572 tothe first gas generating source 571.

[0437] Here, the timing of starting bubbling at the second gasgenerating source 572 during replenishment of the ammonia water to thefirst gas generating source 571 is such a timing at which, when theammonia water is replenished to the first gas generating source 572, astate, where the ammonia gas containing water vapor is generated at thesecond gas generating source 572, is attained. Such a timing or thetiming when the ammonia water at the first and the second gas generatingsources 571, 572 is replenished may be determined by an operator. Or, bydisposing water level sensors to the respective gas generating sources571, 572, thereby the water level of the ammonia water may beautomatically detected, to determine the appropriate timing.

[0438] Further, the switching valves V1, V2, V3, and V4 may be designedto be manually switched by an operator. Or, a controller for controllingswitching of these may be disposed to switch automatically according tothe predetermined timings.

[0439]FIG. 33 is a diagram showing diagrammatically one example of a gasflow path in the aging unit 3 of configuration shown in FIG. 32. In thisexample, ammonia gas is fed to the first and the second gas generatingsources from a common gas feeding source 570. And as shown in FIG. 33,between the valve V1 and the branching point of the treatment gasfeeding pipe 581, a conductance control portion P1 is disposed. Thisconductance control portion P1 is disposed so as to match theconductance from the first gas generating source 571 to the treatmentchamber 560 to the conductance from the second gas generating source 572to the treatment chamber 560. This conductance control portion P1 isprovided with a structure by which the cross section of the gas flowpath, that is, resistance of gas flow can be controlled. Specificcontrol of the conductance is carried out such that, by use of a flowmeter 580 disposed at the gas feeding pipe 581, the flow rate when thegas is flowed from the first gas generating source 571 and that when thegas is flowed from the second gas generating source are made equal.Incidentally, the conductance control portion P1 may be disposed,instead of at the aforementioned position, at positions between from thevalve V2 to the aforementioned branching point, or may be disposed onboth positions.

[0440] In addition, even on the first bypass (the first exhaust path)582 reaching directly to the exhaust path 565 from the first gasgenerating source 571 without through the treatment chamber 560 butthrough the valve V3, a conductance controlling portion P2 is disposed.The conductance of this conductance controlling portion P2 is set theconductance of the whole gas flow path from the first gas generatingsource 571 through the valve V3 on the exhaust side, the conductancecontrolling portion P2, and the first bypass 582 to the exhaust path565, to be equal with the conductance of the whole gas flow path fromthe first gas generating source 571 through the valve V1 on thetreatment chamber side and the treatment chamber 560 to the exhaust path565.

[0441] Further, even on the second bypass (the second exhaust path) 583from the second gas generating source 572 without through the treatmentchamber 560 but through the valve V4 directly to the exhaust path 565,the conductance controlling portion P3 is disposed. The conductance ofthis conductance controlling portion P3 is set the conductance of thewhole gas flow path from the second gas generating source 572 throughthe valve V4 on the exhaust side, and the second bypass 583 to theexhaust path 565 to be equal with that of the whole gas flow path fromthe second gas generating source through the valve V2 on the treatmentchamber 560 side and the treatment chamber 560 to the exhaust path 565.

[0442] By controlling the conductance of the gas flow path like this,when, while letting gas flow from the first gas generating source 571 tothe bypass 582 for instance, an wafer is introduced into the treatmentchamber 560 and the gas flow path is switched to the treatment chamber560 side, or when the feeding source of the treatment gas to thetreatment chamber 560 is switched between the first gas generatingsource 571 and the second gas generating source 572, the fluctuation ofthe flow rate of the treatment gas and the pressure inside the treatmentchamber 560 can be suppressed. For instance, provided that the first gasgenerating source 571 is switched to the second gas generating source572, the gas flow from the first gas generating source 571 to thetreatment chamber 560 is stopped, and at the same time, the gas flowfrom the second gas generating source 572 to the bypass 583 is switchedto the valve V2 side. In this case, as mentioned above, since theconductances of the respective flow paths were made equal, the pressureand flow rate of the gas flowing into the treatment chamber 560, thoughbeing varied a little due to switching of the valve, hardly showfluctuation. This situation is identical when the source of thetreatment gas is returned from the second gas generating source 572 tothe first gas generating source 571.

[0443] According to the aforementioned example 8, simultaneously withthe first treatment step where an wafer W is treated by feeding anammonia gas containing water vapor from the first gas generating source571 to the inside of the treatment chamber 560, even at the second gasgenerating source 572, by letting the ammonia gas containing water vaporgenerate, preparatory exhaust step of releasing the ammonia gascontaining water vapor directly to the exhaust path 565 through thebypass 583 is carried out, and when the ammonia water is replenished tothe first gas generating source 571, the feeding source of the treatmentgas to the treatment chamber 560 is switched from the first gasgenerating source 571 to the second gas generating source 572, therebythe second treatment step of treating the wafer W is carried out,accordingly upon replenishing the ammonia water feeding of the treatmentgas is not interrupted.

[0444] Further, according to the aforementioned example 8, since theammonia water 573 in the first and the second gas generating sources571, 572 is always being held at the normal temperature by thetemperature controlling water, the temperature fluctuation due tovaporization and absorption of ammonia can be suppressed, therebyfluctuation of water vapor is suppressed, resulting in stabilization ofthe process. In the case of ammonia water particularly, since a slighttemperature variation induces a large variation of the saturatedconcentration, the generating amount of the gas is considered tofluctuate due to the external temperature disturbance. However,according to example 8, the flow rate of the ammonia gas can bestabilized.

[0445] Further, upon introducing the ammonia gas after carrying in anwafer W into the treatment chamber 560, since the conductance of theeach gas flow path of the bypass 582 side and the treatment chamber 560side is equal each other, upon switching the valves V1 and V3, theammonia gas is introduced from the beginning with the predeterminedpressure and flow rate. Further, even when the first gas generatingsource and the second gas generating source 571, 572 are switched, thepressure and the flow rate of the ammonia gas do hardly fluctuate,accordingly the gelling treatment can be carried out with stability. Asthe result, the film thickness and film quality of the coated films canbe suppressed from fluctuating, uniform treatment between the wafers canbe carried out. Further, since the ammonia water can be replenishedwithout interrupting operation each time, thereby lowering of throughputcan be prevented from occurring.

[0446] In the aforementioned sixth invention, various variations can beapplicable. The temperature control means 577, for instance, canmaintain the ammonia water 573 in the tank 574 at the normal temperatureby winding the tank 574 of the first gas generating source 571 and thesecond gas generating source 572 by a heater of resistance heating orthe like, or by employing an immersion heater. Further, the valves V1and V2 can be substituted by a single 3-way valve.

[0447] Further, the sixth invention, as shown in FIG. 34, can be aconfiguration in which a single gas generating source 579 generating anammonia gas saturated by water vapor is connected to the treatmentchamber 560. The gas generating source 579 can be constituted asidentical as the first gas generating source 571 or the second gasgenerating source 572 shown in FIG. 33. In this example, a switchingvalve VS is disposed at the midway of the treatment gas feeding pipe 581which communicates and connects the gas generating source 579 and thetreatment chamber 560. And, a bypass 584 is disposed branched betweenthe valve VS and the gas generating source 579. This bypass 584 iscommunicated and connected to the exhaust path 565 through the switchingvalve V6 and the conductance control portion P4. By conductance controlportion P4, the conductance of the flow path through the treatmentchamber 560 and that of the flow path through the bypass 584 are madeequal.

[0448] According to the example shown in FIG. 34, after replenishment ofthe ammonia water, the preparatory exhaust step of releasing directly tothe exhaust path 565 through the bypass 584 is carried out until theconcentration of the ammonia water is stabilized at the predeterminedconcentration, and when subsequently the flow path is switched to thetreatment chamber 560 side, since the conductance of the flow pathbefore and after switching are equal, the ammonia gas can be fed withthe predetermined flow rate into the treatment chamber 560 from thebeginning, therefore, the stable gelling treatment can be carried out.In order to carry out treatment step of treating the wafer W by feedingthe ammonia gas saturated by water vapor into the treatment chamber 560by switching the valve V5 and the valve V6 to open state and closedstate, respectively, with stability, the ammonia gas containing watervapor can be always introduced into the treatment chamber 560. Further,since, through the temperature control of the ammonia water of the gasgenerating source 579 and the conductance control of the gas flow path,the treatment temperature, the flow rate of the treatment gas and thepressure in the treatment chamber 560 can be held at the constantvalues, uniform treatment can be carried out between the wafers, therebythe fluctuation of the film quality between the wafers can besuppressed.

[0449] Incidentally, the subject to be treated is not restricted to thewafer, but can be a glass substrate for liquid display device. Further,the sixth invention is not restricted to the case of gelling by use ofthe ammonia gas. It can be applied to a device in which, for instance,while exhausting the treatment gas from the bypass, the subject to betreated is carried into the treatment chamber, thereafter by switchingthe flow path from the bypass to the treatment chamber side, thetreatment gas is introduced.

[0450] Further, in the aforementioned example 8, by disposing 2 tanks574 of ammonia, the ammonia gas generated therefrom is switched in turn,but 3 and more of tanks 574 can be disposed. In that case, whileshifting the timings generating ammonia from the respective tanks 574,by switching 3 tanks 574 and the feeding pipe 581 in turn, the ammoniagas can be flowed always at a constant flow rate.

[0451] As shown in the above, according to the sixth invention, in thecase of treatment being carried out by introducing the treatment gasinto the treatment chamber, the stable treatment can be carried out.

EXAMPLE 9

[0452] Next, example 9 involving the seventh invention of the presentapplication will be described.

[0453]FIG. 36 is a plan view showing diagrammatically the wholeconfiguration of the apparatus of forming a film of example 7 involvingthe seventh invention of the present application.

[0454] In the figure, reference numeral 611 denotes an input/output portof wafers W which are substrates, reference numeral 612 denotes acarrying arm constituting a receiving portion, and reference numeral 613denotes a main arm constituting a main carrying portion. On one side ofa carrying way (guide rail) 614 of the main arm 613, a coating /agingunit 620 provided with a coating unit 620 which is a coating portion andan aging unit 630 which is a gelling treatment portion, and a solventreplacement unit 640 which is a solvent replacement portion are arrangedin this order.

[0455] Further, also on the other side of the carrying way 614, thetreatment units U1 through U4 are arranged.

[0456] To these treatment units U1 through U4, the units for carryingout hydrophobic treatment, cooling treatment and heat treatment (baketreatment) are respectively assigned. In this example 9, the unit forcarrying out the hydrophobic treatment and the cooling treatmentcorresponds to the pretreatment portion for carrying out the treatmentpreceding the coating of the coating liquid on the wafer W. Further, theunit for carrying out the heat treatment corresponds to the heatingportion for drying the wafer W treated at the aging unit 630.

[0457] The carrying arm 612 and the main arm 613 are constituted to becapable of moving freely in the X direction and in the Y direction, andto be capable of rotating freely. An wafer W is taken out of a cassetteC disposed on a cassette stage CS by the carrying arm 612 and isdelivered to the main arm 613. Further, the wafer W is sequentiallycarried by the main arm 613 to the respective units 620, 640, and U1through U4.

[0458] Subsequently, the coating/aging unit 620 will be described withreference to FIG. 37 through FIG. 39. To this coating/aging unit 620, asshown in FIG. 37, a coating unit 620 and an aging unit 630, forinstance, are disposed adjacent thereto.

[0459] First, the coating unit 620 will be described with reference toFIG. 38. The coating unit 620 comprises a fixed cup 622 foraccommodating an wafer W, a cover 621 opening and closing an upperopening thereof, a vacuum chuck 625 disposed to be capable of rotatingin the fixed cup 622, and a coating liquid nozzle 626 for dispensing thecoating liquid on the wafer W held on the vacuum chuck 625.

[0460] At the bottom portion of the fixed cup 622, a breakthrough isopened, therethrough a rotation axis 624 is inserted. The upper end ofthis rotation axis 624 is combined with the vacuum chuck 625, the lowerend of the other rotation axis 624 is combined to a driving portion 623disposed below the lower side of the fixed cup 622. Through thisrotation axis 624, driving force of rotation is transmitted from thedriving portion 623 to the vacuum chuck 625. Further, the rotation axis624 is capable of going up and down in the up/down direction. Thecoating liquid nozzle 626 is disposed combined with the cover 621 andthe coating liquid is dispensed on the central portion of the wafer W.

[0461] To the cup 622, a solvent vapor feeding pipe 627 for feeding thevapor of the solvent which is sent from the solvent vapor generatingsource 627 a and is employed in the coating liquid is connected. To thecup 622, a drain pipe 628 and an exhaust pipe 629 are further connected.

[0462] Next, the aging unit 630 will be described with reference to FIG.39. This aging unit 630 comprises a heating plate 631 consisting ofceramic, for instance, including a heater 631 a, and a cover 633disposed adjacent to the upper side of the heating plate 631 so as toform a space S, which constitutes a treatment chamber there, bypartitioning the upper space of the heating plate 631.

[0463] The cover 633 is, in addition to being intimately connected tothe brim portion of the heating plate 631 through a sealing member 632,free in contacting and detaching with respect to the heating plate 631.

[0464] On the upper surface of the heating plate 631, a groove like gassupply is formed such that surrounds the exterior circumference of thewafer W to be placed on the heating plate 631, the bottom portion ofthis gas supply is connected to the gas feeding path 634.

[0465] On the central portion of the cover 633, an intake for inhaling agas is formed, and this intake is connected to an exhaust path 635communicating with the exterior.

[0466] The bottom portion of the heating plate 631, 3 pieces of pins 636for going up and down disposed to be capable of appearing anddisappearing freely are provided. These pins 636 for going up and downgoes up and down the wafer W between the heating plate 631 and the aboveposition thereof. Incidentally, a heating means such as a heater ispreferably disposed even to the cover 633.

[0467] These fixed cup 622 and aging unit 630 of the coating unit 620,as shown in FIG. 37, are disposed adjacent each other on a common levelbase stage 650. And, between these units 620 and 630 on the base stage650, a sub-arm mechanism constituting an auxiliary carrying portion isdisposed.

[0468] This sub-arm mechanism 5 is exclusively used for carrying thewafer W treated at the coating unit 620 to the aging unit 630. For this,together with disposition of, for instance, a sub-arm 651 for holding apart of the circumference portion of the bottom surface of the wafer W,this sub-arm 651 is constituted to be capable of moving in the leveldirection (the X direction in FIG. 1) along a guide rail 652, inaddition, the guide rail 652 itself is constituted to be capable ofrotating in the level direction through a vertical rotation axis 654 bya driving portion 653. Thus, the sub-arm 651 is capable of reversing thedirection between the coating unit 620 and the aging unit 630 forreceiving the wafer W. At the same time, the sub-arm is capable ofmoving between an waiting position (the position shown by the solid linein FIG. 37) and a position receiving the wafer W from the coating unit620, and between the waiting position and a position delivering thewafer W to the aging unit 630. Further, in this example, the guide rail652 is disposed at the above side than the base stage 650.

[0469] Further, above the sub-arm 651, above the guide rail 652 of thecarrying path of the wafer W between the coating unit 620 and the agingunit 630, a solvent vapor feeding portion 655 which is a means forfeeding vapor of the solvent component which is employed in the coatingliquid is disposed. This solvent vapor feeding portion 655 comprises adispersing room 656 for dispersing the solvent vapor and a vapordiffusing plate 657. The dispersing room 656 is disposed so as toopposes the sub-arm 651 in the waiting position, and the diffusing plate657 is attached to the bottom surface of the dispersing room 656 and hasa structure in which a plurality of steam holes 657 a are bored. To thedispersing room 656, a solvent vapor feeding pipe 658, for instance, forfeeding the solvent vapor generated at a solvent vapor generatingsource, which is not shown in the figure, is connected.

[0470] Subsequently, the solvent replacement unit 640 will be describedwith reference to FIG. 40.

[0471] This unit 640 comprises a vacuum chuck 641 rotating the wafer Wwhile holding it in level, a rotary cup 642 which is disposed tosurround the wafer W on this chuck 641 and has a hole 640 for exhaustingliquid, a fixed cup 643 which is disposed outside the rotary cup 642 andin which an waste liquid path 641 a and an waste gas path 641 b areconnected, and a nozzle 644 for dispensing the solvent to the wafer W.Further, reference numeral 645 in the figure denotes a driving portionfor rotating and going up and down the rotation axis 641 a of the chuck641, and reference numeral 642 a denotes a driving portion for rotatingthe rotary cup 640.

[0472] The opening on the upper surface of the fixed cup 643 is openedand closed by a cover 646 capable of going up and down. Further, as thenozzle 644 in this example, 3 pieces of nozzles 644 a, 644 b, and 644 cfor ejecting ethanol, HMDS (hexamethyl disilane) and heptane,respectively, are prepared. These nozzles 644 a, 644 b, and 644 c aregrasped and taken out of the nozzle receiving portions 648 a, 648 b, and648 c, respectively, and are transferred to the above of the centralportion of the wafer W.

[0473] In this apparatus of forming a film, the wafer W undergone thehydrophobic treatment and the cooling treatment is carried in turn tothe coating/aging unit 620, the solvent replacement unit 640, and theunit for carrying out bake treatment, and by carrying out thepredetermined treatment at the respective units, an interlayerinsulating film consisting of a silicon oxide film is formed on thesurface of the wafer W.

[0474] Subsequently, the treatments carried out at the coating/agingunit 620 and the solvent replacement unit will be described. First, atthe coating/aging unit 620, the coating liquid is coated on the surfaceof the wafer W at the coating unit 620 to form a coated film.Thereafter, the wafer W is carried to the aging unit 630 by the sub-arm651. Then, the particles or the colloids of the coated film formed onthe wafer W at the unit 630 are gelled.

[0475] In specific, at the coating unit 620, the wafer W carried to thecoating unit 620 by the main arm 613 is delivered to the chuck 625 atthe position of the dotted line in FIG. 38 for instance, after the chuck625 is lowered, the cup 622 is sealed by the cover 621. The coatingliquid used here can be prepared by dispersing the colloids or particlesof TEOS which is a metal alkoxide in the solvent which contains organicsolvent such as ethylene glycol and ethyl alcohol, water and a trace ofhydrochloric acid. Ethylene glycol plays, other than the role of, uponcoating, adjusting the viscosity of the coating liquid to an appropriatevalue, another role of suppressing vaporization of ethyl alcohol byremaining there as the solvent because, at the steps after the coatingstep, ethyl alcohol the vapor pressure of which is low vaporizes almostcompletely. This is based on the higher vapor pressure of ethyleneglycol.

[0476] And, in this example, while exhausting from the exhaust pipe 629,the vapor of ethylene glycol is fed into the cup 622 from the solventvapor feeding pipe 627. The exhausting is ceased after the inside of thecup 622 is filled by the vapor of ethylene glycol, and the coatingliquid is fed on the central portion of the wafer W from the nozzle 626.Then, the wafer W is rotated by the chuck 625, the coating liquid isspread on the surface of the wafer W due to centrifugal force to form afilm. The reason why the treatment is carried out in such a state wherethe inside of the cup 622 is filled by the vapor of ethylene glycol isto suppress the vaporization of the solvent in the coating liquid.Incidentally, though not shown in the figure, thereafter, the solvent issprayed on the circumference portion of the wafer W from the nozzle inthe cup 622 to remove the coated film of the circumference portion.

[0477] After the coating treatment is carried out thus at the coatingunit 620, the wafer W is carried to the aging unit 630 by the sub-arm651. First, in a state where the cover 621 is lifted a little forinstance, the inside of the cup 622 is evacuated, after the cover 621and the chuck 625 are raised, the wafer W is delivered from the chuck625 to the sub-arm 651. That is, the solvent vapor such as that ofethylene glycol is fed on the guide rail 652 from the solvent vaporfeeding portion 655, the direction of the sub-arm 651 is turned to theside of the coating unit 620, the sub-arm 651 is moved from the waitingposition to the position where the wafer W is received from the coatingunit 620, and the wafer W is delivered from the chuck 625 to the sub-arm651.

[0478] Then, the cover 633 of the aging unit 630 is raised, thedirection of the sub-arm 651 is turned to the side of the aging unit630, the sub-arm 651 is moved to the position where the wafer W isdelivered to the aging unit 630, by cooperation of the pins 636 forgoing up and down and the sub-arm 651, the wafer W is delivered from thesub-arm 651 on the heating plate 631.

[0479] Next, at the aging unit 630, the colloids of TEOS contained inthe coated film on the wafer W is gelled, to link the colloidsreticular. That is, at the aging unit 630, after the wafer W is placedon the heating plate 631, the cover 633 is closed, while evacuating fromthe exhaust path 635, the vapor of ethylene glycol for instance isintroduced into the treatment chamber from the gas feeding path 634.Here, the wafer W is heated to the temperature of around 100° C., forinstance.

[0480] The treatment of linking the colloids reticular by gelling thecolloids of TEOS is expedited by heating the coated film, however, byemploying an ammonia gas instead of heating, the ammonia gas is operatedon TEOS as a catalyst, thereby the gelling may be expedited. Further,the reason why the vapor of ethylene glycol is introduced into thetreatment chamber is to suppress the vaporization of the solvent in thecoated film, therefore, the piping and the vapor generating source arecontrolled in their temperature such that the vapor is saturated (100%by the relative humidity of ethylene glycol) at the temperature of thetreatment chamber, for instance.

[0481] Subsequently, the treatment carried out at the solventreplacement unit 640 will be described. The wafer W treated at the agingunit 630 is delivered from the heating plate 631 to the main arm 613,then is transferred to the solvent replacement unit 640 by this main arm613. And, at this unit 640, a solvent other than the solvent of thecoating liquid is fed, thereby the solvent in the coated film formed onthe wafer W is replaced by the other solvent.

[0482] In specific, in a state where the cover 646 is open, at the aboveposition of the fixed cup 643, the wafer W is delivered to the chuck 641from the main arm 613, and the chuck 641 is lowered. Then, first,together with dripping chemicals in which moisture is soluble, forinstance, ethanol on the approximately central portion of the wafer Wfrom the nozzle 644 a, the wafer W and the rotary cup 642 are rotated,thereby ethanol is diffused over the whole surface of the wafer W due tothe centrifugal force. Thereby, ethanol dissolves in the moisture in thecoated film, resulting in replacement of the moisture by ethanol.

[0483] Subsequently, the cover 646 is opened, similarly HMDS isdispensed on the approximate rotation center of the wafer W to remove OHgroups in the coated film. Further, by dispensing heptane on theapproximate rotation center of the wafer W, the solvent in the coatedfilm is replaced by heptane. The reason why heptane is employed here isto prevent the reticular structure of TEOS from collapsing by reducingthe force added on the porous structure, namely, reticular structure ofTEOS through use of the solvent of low surface tension. Incidentally,the above example of the solvent replacement unit 640 is described ofthe jacketed cup structure consisting of the fixed cup 643 and therotary cup 642, however, as identical as the coating unit 620, astructure with only a fixed cup may be employed.

[0484] In the aforementioned example 9, the coating unit 620 and theaging unit 630 are disposed adjacently inside the same unit 620, therebythe wafer W is transferred by an exclusive sub-arm 651 from the coatingunit 620 to the aging unit 630. Therefore, the wafer W on which thecoating treatment is carried out at the coating unit 620 is transferredwithout delay to the aging unit 630 without waiting transfer of thewafer W and is treated. Accordingly, since gelling treatment can becarried out in a state where the vaporization of the solvent in thecoated film is suppressed, desired film thickness and film quality canbe secured.

[0485] Further, the distance of the transfer path between the coatingunit 620 and the aging unit 630 is short, accordingly the transfer timebecomes short. Accordingly, vaporization of the solvent in the coatedfilm during transfer can be reduced further more. Further, since thevapor of ethylene glycol is supplied on the transfer path, thevaporization of the solvent during transfer is further suppressed bythis ethylene glycol.

[0486] When there is no sub-arm 651, transfer between the coating unit620 and the aging unit 630 is carried out by the main arm 613.Therefore, even if the coating treatment is completed, in the case ofthe main arm 613 being employed for transfer between the other units, itis required to wait for the main arm 613. Further, since the main arm613 moves along the guide rail 614 in the center, the transfer pathbetween the coating unit 620 and the aging unit 630 becomes long,resulting in the longer transfer time. Therefore, since it takes a longtime to transfer the wafer W from the coating unit 620 to the aging unit630, the amount of vaporization of the solvent in the coated film isliable to increase.

[0487] Subsequently, modification example of example 9 will be describedwith reference to FIG. 41 and FIG. 42. This example is characterized inthat, together with covering the whole coating and aging unit 620 by thetreatment chamber (case) 660, the inside of the treatment chamber 660 isfilled by the vapor of the solvent component of the coated film such asethylene glycol. On the side wall opposite to the guide rail 614 of thetreatment chamber 660, an opening 661 a for delivering the wafer W fromthe main arm 613 to the coating unit 620, and an opening 661 b fordelivering the wafer W from the aging unit 630 to the main arm 613 arerespectively disposed on the appropriate positions, and these openings661 a, 661 b are always closed by the doors 662 a, 662 b.

[0488] Further, to the treatment chamber 660, a solvent vapor feedingpipe 664 for feeding the vapor of ethylene glycol generated at thesolvent vapor generating source 663 and an exhaust pipe 665 areconnected respectively. In this example, a means for feeding the vaporof the solvent component into the treatment chamber 660 is constitutedof the solvent vapor generating source 663 and the solvent vapor feedingpipe 664.

[0489] In this example, while evacuating the inside of the treatmentchamber 660, by feeding the vapor of ethylene glycol into the treatmentchamber 660, the inside of the treatment chamber, for instance, isadjusted to be saturated by the vapor of ethylene glycol. Then, in astate where the inside of the treatment chamber 660 is made theatmosphere of ethylene glycol, the door 662 a is opened, the wafer W isdelivered from the main arm 613 on the chuck 625 of the coating unit620, and the door 662 a is closed. Then, treatment for forming a coatedfilm is carried out as described above, the wafer W is transferred fromthe coating unit 620 to the aging unit 630 by the sub-arm 651, and atthe aging unit 630 gelling treatment is carried out. Thereafter, thedoor 662 b is opened, and the wafer W is delivered from the heatingplate 631 to the main arm 613.

[0490] In such a configuration, since the treatment chamber is filled bythe vapor of ethylene glycol, all over the steps from the execution ofthe coating treatment at the coating unit 620 up to the execution ofgelling treatment at the aging unit 630, the vaporization of the solventin the coated film can be suppressed. Since the gelling of the coatedfilm is further suppressed thereby, the thin film of more excellentquality can be formed.

[0491] Subsequently, still another modification example of example 9will be described with reference to FIG. 43. In this example, a coatingunit 620 and an aging unit 630 and a solvent replacement unit 640 aredisposed adjacently in the same unit 670 in this order, and, between theaging unit 630 and the solvent replacement unit 640, a sub-arm mechanism672 constituting an auxiliary transfer portion for transferringexclusively the wafer W treated at the aging unit 630 to the solventreplacement unit 640 is disposed.

[0492] Also in this example, between the coating unit 620 and the agingunit 630, a sub-arm mechanism 650 for exclusively transferring the waferW treated at the coating unit 620 to the aging unit 630 is disposed, thesub-arm mechanism 670 between the aging unit 630 and the solventreplacement unit 640 is constituted identically as the sub-arm mechanism650. That is, the sub-arm 671, together with the direction beingreversed between the aging unit 630 and the solvent replacement unit640, is constituted to be capable of moving along the guide rail(transferring path) 672 between the both units 630, 640.

[0493] In this example, the wafer W is delivered from the main arm 613onto the chuck 625 of the coating unit 620, after the coating treatmentis carried out at the coating unit 620, the wafer W is transferred tothe aging unit 630 by the sub-arm 651, to deliver to the heating plate631. Then, after the gelling treatment is carried out at this unit 630,the wafer W is delivered to the sub-arm 671 to transfer to the solventreplacement unit 640, then is delivered to the chuck 641. And, aftersolvent replacement treatment is carried out at this unit 640, the waferW is delivered from the chuck 641 to the main arm 613, and the wafer Wis transferred by the-arm 613 to a unit for carrying out bake treatment.

[0494] In such a configuration, not only between the coating unit 620and the aging unit 630, but also between the aging unit 630 and thesolvent replacement unit 640, transfer of the wafer W is carried outwithout delay. Accordingly, since the gelling treatment can be carriedout in a state where vaporization of the solvent in the coated film issuppressed, in addition to suppression of film shrinkage anddeterioration of the film quality, the time period during which thelarge surface tension of the solvent is added on the reticular structureof TEOS is short, accordingly collapse of the film structure issuppressed, resulting in a thin film of further excellent quality.

[0495] In the aforementioned seventh invention, the auxiliary transferportion may be constituted as shown in FIG. 44. In this example, forinstance, a coating unit 620, an aging unit 630, and a solventreplacement unit 640 are constituted as different units each other. Theauxiliary transfer portion 680 is provided with a pair of arm members681 a, 681 b which hold the wafer W by nipping a part of bothcircumference portions of the wafer W for instance, and these armmembers 681 a, 681 b are constituted to be capable of freely opening andclosing in the Y direction for instance by an opening and closingmechanism 682. Further, the opening and closing mechanism 682 isconstituted to be movable in the X direction along the guide rail 683 ata position above the respective units 620, 630, and 640.

[0496] In such a configuration, the wafer W is exclusively transferredalong the guide rail 683 from the coating unit 620 to the aging unit630, and from the aging unit 630 to the solvent replacement unit 640,held by the arm members 681 a, 681 b.

[0497] Therefore, even in the case of these units 620, 630, and 640being constituted as the separate units, the wafer W is transferredwithout delay between these units, as the result, the vaporization ofthe solvent in the coated film can be suppressed, accordinglydeterioration of the film quality of the thin film can be prevented fromoccurring.

[0498] Incidentally, this auxiliary transfer portion can be applied evenin the case of the coating unit 620, the aging unit 630, and the solventreplacement unit 640 being constituted as the same unit, also can beapplied for transfer only between the coating unit 620 and the agingunit 630.

[0499] Further, the seventh invention can be applied even in theapparatus of forming a film of vertical type as shown in FIG. 45. Theapparatus will be briefly described with reference to FIG. 45. Referencenumeral 691 in the figure denotes a main arm constituted to be capableof freely going up and down, freely moving forward and backward, andfreely rotating, and, on one side (left side) of the main arm 691, ahydrophobic treatment unit 692 which is a pre-treatment step forcarrying out the hydrophobic treatment of the wafer W, and 5 heatingunits 693 a through 693 e, for instance, constituting the heatingportion for carrying out heat treatment (bake treatment) to the wafer Ware piled up from the bottom in this order.

[0500] On the other hand, on the other side (right side) of the main arm691, a receiving portion 694 for receiving the wafer W from outside theapparatus, a coating unit 620, an aging unit 630, and a solventreplacement unit 640 are piled up from the bottom in this order. Thus,on both sides of the main arm 691, a plurality of unit groups aredisposed respectively, and, between these unit groups, a transfer pathof the main arm 691 is formed. On the side portion of the coating unit620 and the aging unit 630, for instance, the opposite side of thetransfer path of the main arm 691, in a case 695, the sub-arm 696constituting the auxiliary transfer portion is disposed to be capable offreely going up and down, freely moving forward and backward, and freelyrotating, and the inside of the case 695 is a transfer path of thesub-arm 696.

[0501] Even in such a configuration, since the wafer W is exclusivelytransferred between the coating unit 620 and the aging unit 630 by thesub-arm 696, transfer between these units 620, 630 is carried outwithout delay. Accordingly, vaporization of the solvent in the coatedfilm can be suppressed and the film quality of the thin film isprevented from deteriorating. Also in this example, the inside of thecase 695 may be made an atmosphere of ethylene glycol, or, by extendingthe case 695 up to the side of the solvent replacement unit 640, thewafer W may be exclusively transferred between the aging unit 630 andthe solvent replacement unit 640 by the sub-arm 696. Incidentally, inthe seventh invention, the substrate is not restricted to the wafer butcan be glass substrate for liquid crystal display.

[0502] According to the seventh invention, after the coating liquid inwhich colloids or particles of the starting material of the filmcomponent are dispersed in the solvent is coated on the substrate, thesubsequent step can be carried out without delay, accordingly a thinfilm of excellent quality such as an interlayer insulating film can beobtained.

What is claimed is:
 1. A method of forming a film, comprising: a coatingstep of forming a film by coating a coating liquid, in which particlesor colloids of a starting substance of a film component are dispersed ina solvent, on a surface of a substrate; a first gelling step of,together with carrying the substrate into a sealed chamber, gelling thesubstrate in a state where the substrate is exposed to a gas containinga solvent vapor of the coating liquid at a first average concentration;and a second gelling step of gelling in a state where the inside of thesealed chamber is filled by a gas containing the solvent vapor of thecoating liquid at a second average concentration higher than the firstaverage concentration.
 2. The method of forming a film as set forth inclaim 1 : wherein a gas to be introduced in the sealed chamber in thefirst gelling step is controlled such that temperature thereof is closeto that inside the sealed chamber.
 3. The method of forming a film asset forth in claim 1 , further comprising: preceding the first gellingstep, a step of, together with generating a mixed gas of a vapor of asolvent component and a carrier gas, exhausting the mixed gas byswitching a valve to exhaust side; wherein an operation of, in the firstgelling step, exposing the substrate to the gas containing the solventvapor of the coating liquid at the first average concentration iscarried out by introducing the mixed gas into the sealed chamber byswitching the valve.
 4. The method of forming a film as set forth inclaim 1 : wherein the gelling step is a step of heating the substrate.5. The method of forming a film as set forth in claim 1 : wherein thegas is generated by mixing a carrier gas and a vapor of a solventcomponent; wherein the first gelling step is carried out by controllinga flow rate of at least one of the carrier gas or the vapor of thesolvent component.
 6. The method of forming a film as set forth in claim1 : wherein the mixing of the carrier gas and the vapor of the solventcomponent is carried out at a vaporizer vaporizing a liquid of thesolvent component, and the first gelling step is carried out bycontrolling a flow rate of the liquid of the solvent component beingintroduced into the vaporizer.
 7. The method of forming a film as setforth in claim 1 : wherein the first gelling step includes a step ofvarying continuously a concentration of the vapor of the solventcomponent.
 8. The method of forming a film as set forth in claim 1:wherein the first gelling step includes a step of mixing intermittentlythe vapor of the solvent component into the carrier gas.
 9. The methodof forming a film as set forth in claim 1 , further comprising: a stepof, up to before exposing the substrate to a gas after carrying thesubstrate into a sealed chamber, feeding the gas into a sealed chamberin a state where an average concentration of the vapor of the solventcomponent is higher than an average concentration during the firstgelling step.
 10. The method of forming a film as set forth in claim 1 :wherein the first average concentration is a concentration correspondingto a saturated vapor pressure at a substrate temperature during transferinto a chamber; and wherein the second average concentration is aconcentration corresponding to a saturated vapor pressure at a substratetemperature during gelling.
 11. An aging unit comprises: a treatmentchamber accommodating a substrate formed thereon a film containing asolvent and particles or colloids of a starting substance of a filmcomponent; a heater for heating the substrate; a carrier gas feedingsystem for feeding the carrier gas toward the treatment chamber; asolvent dispensing system for dispensing the solvent toward thetreatment chamber; a mixing system for forming a mixed gas containing asolvent vapor from the carrier gas feeding system and the solventdispensing system; and a control mechanism for controlling a solventconcentration of the mixed gas.
 12. An apparatus of forming a filmcomprises: a coating unit for coating, on a surface of a substrate, acoating liquid in which particles or colloids of a starting substance ofa film component are dispersed in a solvent; an aging unit comprising atreatment chamber for accommodating the substrate formed thereon thefilm, a heater for heating the substrate, a carrier gas feeding systemfor feeding the carrier gas toward the treatment chamber, a solventdispensing system for dispensing the solvent toward the treatmentchamber, a mixing system for forming a mixed gas containing a solventvapor from the carrier gas feeding system and the solvent dispensingsystem, and a control mechanism for controlling a solvent concentrationof the mixed gas; and a solvent replacement unit for replacing thesolvent in the film.
 13. A method of forming a film, comprising: a stepof forming a film by coating, on a surface of a substrate, a coatingliquid in which particles or colloids of a starting substance of a filmcomponent are dispersed in a solvent; a step of gelling the particles orthe colloids in the film; and a step of dispensing, on the surface ofthe substrate, at least 2 kinds of replacement solvents different fromthe solvent by switching them sequentially; wherein switching of thereplacement solvent to be fed is carried out by, after subsequentreplacement solvent is began in dispensing while dispensing a precedingreplacement solvent, stopping dispensing of the preceding replacementsolvent.
 14. The method of forming a film as set forth in claim 13 :wherein the at least 2 kinds of solvents are dispensed to the substratefrom a common solvent dispensing portion:
 15. The method of forming afilm as set forth in claim 13 : wherein the at least 2 kinds of solventsare dispensed to the substrate from separate solvent dispensingportions.
 16. The method of forming a film as set forth in claim 13 :wherein the step of dispensing by switching sequentially the replacementsolvent is a step of dispensing on the substrate an alcohol, ahydrophobic treatment liquid, and a solvent of smaller surface tensionthan solvents included in the coating liquid in this order.
 17. Asolvent replacement unit, comprises: a treatment chamber accommodating asubstrate formed thereon a film containing a solvent and particles orcolloids of a starting substance of a film component; a spin chuckholding the substrate disposed in the treatment chamber; a plurality ofsolvent dispensing systems for dispensing solvents to the substrate; anda switching device for switching the plurality of solvent dispensingsystems.
 18. An apparatus of forming a film, comprises: a coating unitfor forming a film by coating a coating liquid in which particles orcolloids of a starting substance of a film component are dispersed in asolvent on a surface of a substrate; an aging unit for gelling the film;and a solvent replacement unit comprising a treatment chamberaccommodating the substrate formed thereon the film containing thesolvent and the particles or colloids of the starting substance of thefilm component, a spin chuck holding the substrate disposed in thetreatment chamber, a plurality of solvent dispensing systems dispensingthe solvents to the substrate, and a switching device switching theplurality of solvent dispensing systems.
 19. A method of forming a film,comprising: a step of forming a film on a surface of a substrate bycoating a coating liquid in which particles or colloids of a startingsubstance of a film component are dispersed in a solvent under anatmosphere that is filled by a vapor of the solvent; and a step ofgelling the particles or colloids in the film.
 20. A method of forming afilm, comprising: a step of carrying in a substrate from an intake intoa treatment chamber; a step of closing the intake of the treatmentchamber; a step of filling the treatment chamber by a solvent vapor; astep of coating, on a surface of the substrate, a coating liquid inwhich particles or colloids of a starting substance of a film componentare dispersed in the solvent in the treatment chamber filled by thevapor; and a step of gelling the particles or colloids in the film. 21.The method of forming a film as set forth in claim 20 , furthercomprising: a step of removing, after the film is spread on the surfaceof the substrate, while the treatment chamber is being filled by thevapor of the solvent, the film on a circumference portion of thesubstrate by dispensing a cleaning liquid for removing the film on thecircumference portion of the substrate.
 22. A method of forming a film,comprising: a step of carrying in a substrate into a treatment chamberfrom an intake and placing it on a rotary stage; a step of closing thesubstrate intake of the treatment chamber; a step of filling a vapor ofa solvent into the treatment chamber to fill by the vapor; a step of,together with rotating the rotary stage, dispensing, on a surface of thesubstrate, a coating liquid in which particles or colloids of a startingsubstance of a film component are dispersed in the solvent to spread thecoating liquid on the surface of the substrate; and a step of gellingthe particles or colloids in the film.
 23. The method of forming a filmas set forth in claim 22 , further comprising: a step of, afterspreading the film on the surface of the substrate, while the inside ofthe treatment chamber is being filled by the solvent vapor, dispensing acleaning liquid for removing the film on a circumference portion of thesubstrate to remove the film on the circumference portion.
 24. A coatingunit, comprises: a treatment chamber accommodating a substrate; a spinchuck holding the substrate disposed in the treatment chamber; a coatingliquid nozzle for dispensing a coating liquid to the substrate; acoating liquid dispensing system for dispensing the coating liquid inwhich particles or colloids of a starting substance of a film componentare dispersed in a solvent to the coating liquid nozzle; a solventnozzle for dispensing the solvent into the treatment chamber; and asolvent dispensing system for dispensing the solvent to the solventnozzle.
 25. An apparatus of forming a film, comprises: a coating unit offorming a film on a substrate comprising a treatment chamberaccommodating the substrate, a spin chuck holding the substrate disposedin the treatment chamber, a coating liquid nozzle for dispensing acoating liquid to the substrate, a coating liquid dispensing system fordispensing the coating liquid in which particles or colloids of astarting substance of a film component are dispersed in a solvent to thecoating liquid nozzle, a solvent nozzle for dispensing the solvent intothe treatment chamber, and a solvent dispensing system for dispensingthe solvent to the solvent nozzle; an aging unit for gelling the film;and a solvent replacement unit for replacing the solvent in the film.26. A method of forming a film, comprising: a step of coating, on asurface of a substrate, a solvent which is of lower viscosity than thatof the most viscous solvent component of a coating liquid in whichparticles or colloids of a starting substance of a film component aredispersed in a solvent, and which dissolves the starting substance; astep of forming a film by coating the coating liquid on the surface ofthe substrate; and a step of gelling the particles or colloids in thefilm.
 27. The method of forming a film as set forth in claim 26 :wherein a solution of lower viscosity than the most viscous componentamong the solvent components is one solvent component of the coatingliquid.
 28. The method of forming a film as set forth in claim 26 :wherein the solution of lower viscosity than that of the most viscoussolvent component is an alcohol.
 29. The method of forming a film as setforth in claim 26 , further comprising: a solvent replacement step ofdispensing a solvent different from the solvent on the surface of thesubstrate thereon the film is formed and gelling treatment is carriedout, and of replacing the solvent in the film by the different solvent.30. A coating unit, comprises: a treatment chamber for accommodating asubstrate; a spin chuck for holding the substrate disposed in thetreatment chamber; a solvent nozzle for dispensing a solvent to thesubstrate; a solvent dispensing system for dispensing the solvent to thesolvent nozzle; a coating liquid nozzle for dispensing a coating liquidto the substrate dispensed thereon the solvent; and a coating liquiddispensing system for dispensing the coating liquid in which particlesor colloids of a starting substance of a film component are dispersed inthe solvent to the coating liquid nozzle.
 31. An apparatus of forming afilm, comprises: a coating unit comprising a treatment chamber foraccommodating a substrate; a spin chuck for holding the substratedisposed in the treatment chamber; a solvent nozzle for dispensing asolvent to the substrate; a solvent dispensing system for dispensing thesolvent to the solvent nozzle; a coating liquid nozzle for dispensing acoating liquid to the substrate dispensed thereon the solvent; and acoating liquid dispensing system for dispensing the coating liquid inwhich particles or colloid of a starting substance of a film componentare dispersed in the solvent to the coating liquid nozzle; an aging unitfor gelling the film; and a solvent replacement unit for replacing thesolvent in the coated film.
 32. A method of forming a film, comprising:a step of mixing a first liquid containing particles or colloids of astarting substance of a film component which is insoluble or difficultto be dissolved in water, and water, and a second liquid consisting ofan organic solvent in which water and film component dissolve; a stepof, before elapse of film quality deteriorating time after completion ofmixing, coating a mixed liquid containing the first liquid and thesecond liquid on a surface of a substrate; and a step of gelling theparticles or colloids in the film coated on the substrate.
 33. Themethod of forming a film as set forth in claim 32 : wherein the filmquality deterioration time is 6 min. after completion of mixing.
 34. Amethod of forming a film, comprising: a step of mixing a first liquidcontaining particles or colloids of a starting substance of a filmcomponent which is insoluble or difficult to be dissolved in water, andwater, and a second liquid consisting of an organic solvent in whichwater and the film component dissolve; a step of, before elapse of filmquality deteriorating time which deteriorates quality of the filmobtained by mixing thereof after completion of mixing, coating a mixedliquid containing the first liquid and the second liquid on a surface ofa substrate; a step of cleaning an inside of a flow path of the mixingportion and a downstream side thereof by an organic solvent; and a stepof gelling the particles or colloids in the film coated on thesubstrate.
 35. The method of forming a film as set firth in claim 34 :wherein the film quality deterioration time is 6 min. after completionof mixing.
 36. A method of forming a film, comprising: a step of forminga film by coating a coating liquid in which particles or colloids of astarting substance of a film component are dispersed in a solvent on asurface of a substrate; and a step of gelling the particles or colloidsin the film by exposing the substrate to an ammonia gas; wherein, in thegelling step, an ammonia gas is sequentially introduced into at least 2baths accommodating ammonia water of an ammonia concentration lower thana saturated concentration to generate an ammonia gas, the ammonia gasgenerated in advance is fed to the substrate, thereafter the ammonia gasgenerated subsequently is fed to the substrate, thereby conductance ofthe ammonia gas fed to the substrate is kept constant.
 37. A method offorming a film, comprising: a step of forming a film by coating acoating liquid in which particles or colloids of a starting substance ofa film component are dispersed in a solvent on a surface of a substrate;and a step of gelling the particles or colloids in the film by exposingthe substrate to an ammonia gas; wherein the gelling step comprises: astep of carrying in a substance to be treated into a treatment chamber;a first treatment step of generating the ammonia gas containing watervapor by bubbling the ammonia gas into a first bath reserving ammoniawater of an ammonia concentration lower than a saturated concentrationand of feeding the ammonia gas into the treatment chamber; a step ofgenerating the ammonia gas containing water vapor by bubbling an insideof a second bath reserving ammonia water of an ammonia concentrationlower than a saturated concentration by the ammonia gas, and ofexhausting the ammonia gas without through the treatment chamber; asecond treatment step of switching a gas flow path from the first bathto the treatment chamber to a gas flow path from the second bath to thetreatment chamber, and feeding the ammonia gas generated from the secondbath into the treatment chamber; and a step of replenishing the ammoniawater into the treatment chamber.
 38. The method of forming a film asset forth in claim 37 : wherein the gelling step is a step in whichconductance of a flow path when a gas flows through a treatment chamberfrom a first bath, conductance of a flow path when a gas flows through afirst exhaust path from a first bath, conductance of a flow path when agas flows through a treatment chamber from a second bath, andconductance of a flow path when a gas flows through a second exhaustpath from a second bath are made equal.
 39. A method of forming a film,comprising: a step of forming a film by coating a coating liquid inwhich particles or colloids of a starting substance of a film componentare dispersed in a solvent on a surface of a substrate; and a step ofgelling the particles or colloids in the film by exposing the substrateto an ammonia gas; wherein the gelling step comprises: a step of, bygenerating an ammonia gas containing water vapor by bubbling an insideof a first bath where ammonia water of a lower ammonia concentrationthan a saturated concentration is reserved by the ammonia gas,exhausting the ammonia gas without through a treatment chamber butthrough a first exhaust path; a step of carrying in the substance to betreated into the treatment chamber; a first treatment step of, byswitching subsequently a flow path of the ammonia gas generated from thefirst bath from the first exhaust path to the treatment chamber, feedingthe ammonia gas into the treatment chamber; a step of, during the firsttreatment being carried out, by generating the ammonia gas containingwater vapor by bubbling the second bath where ammonia water of anammonia concentration lower than a saturated concentration is reservedby the ammonia gas, exhausting the ammonia gas without through thetreatment chamber but through the second exhaust path; a step of,together with switching a gas flow path from the first bath to thetreatment chamber to a gas flow path from the second bath to thetreatment chamber, by closing the second exhaust path, feeding theammonia gas generated from the second bath into the treatment chamber;and a step of replenishing the ammonia water into the first bath. 40.The method of forming a film as set forth in claim 39 : wherein, in thegelling step, conductance of a flow path when a gas flows from a firstbath through a treatment chamber, conductance of a flow path when a gasflows from a first bath through a first exhaust path, conductance of aflow path when a gas flows from a second bath through a treatmentchamber, and conductance of a flow path when a gas flows from a secondbath through a second exhaust path, are made equal.
 41. A method offorming a film, comprising: a step of forming a film by coating, on asurface of a substrate, a coating liquid in which particles or colloidsof a starting substance of a film component are dispersed in a solvent;and a step of gelling the particles or colloids in the film by exposingthe substrate to an ammonia gas; wherein the gelling step comprises: apreparatory exhaust step of exhausting a treatment gas from a gasgenerating source without through a treatment chamber but through anexhaust path; a step of carrying in an object to be treated into atreatment chamber; and a step of, by switching a flow path from theexhaust path to the treatment chamber side, treating the object to betreated by feeding the treatment gas from the gas generating source intothe treatment chamber; wherein conductance of a flow path from the gasgenerating source through the treatment chamber and conductance of aflow path through the exhaust path, are made equal.
 42. An aging unit,comprises: a treatment chamber accommodating a substrate; a plurality ofammonia baths reserving ammonia water; a bubbling gas feeding system forfeeding a carrier gas for bubbling to the each ammonia bath; a bubblinggas valve for switching the each bubbling gas feeding system; an exhaustsystem for exhausting a gas generated from the each ammonia bath; anexhaust system valve for switching the each exhaust system; an ammoniagas feeding system for feeding the gas generated at the each ammoniabath to the treatment chamber; an ammonia gas valve for switching theeach ammonia gas feeding system; and a means of, together with openingsequentially the each bubbling gas valve, synchronizing with switchingof each bubbling gas valve, closing in turn the each exhaust systemvalve, and opening in turn the each ammonia gas valve.
 43. An apparatusof forming a film, comprises: a coating unit for coating a coatingliquid on a substrate; an aging unit comprising a treatment chamberaccommodating a substrate; a plurality of ammonia baths reservingammonia water; a bubbling gas feeding system feeding a carrier gas forbubbling in the each ammonia bath; a bubbling gas valve switching theeach bubbling gas feeding system; an exhaust system for exhausting a gasgenerated from the each ammonia bath; an exhaust system valve forswitching the each exhaust system; an ammonia gas feeding system forfeeding the gas generated at the each ammonia bath to the treatmentchamber; an ammonia gas valve for switching the each ammonia gas feedingsystem; and a means of, together with opening sequentially the eachbubbling gas valve, synchronizing with the switching of the eachbubbling gas valve, closing in turn the each exhaust system, and openingin turn the each ammonia gas valve; and a solvent replacement unit forreplacing solvent in a film.
 44. An apparatus of forming a film,comprises: a coating portion for forming a film by coating a coatingliquid in which particles or colloids of a starting substance of a filmcomponent are dispersed in a solvent on a substrate; a gelling treatmentportion which is disposed adjacent to the coating portion and gels theparticles or colloids in the film formed at the coating portion; aplurality of pre-treatment portions for pre-treating in advance ofcoating of the coating liquid on a substrate; a plurality of heatingportions for drying the substrate after treatment at the gellingtreatment portion; a receiving portion for receiving the substrate fromthe exterior; a main carrying portion for, together with carrying thesubstrate to the coating portion through the pre-treatment portion afterreceipt of the substrate from the receiving portion, carrying thesubstrate treated at the gelling treatment portion to the later heatingportion; and an auxiliary carrying portion carrying the substrate coatedat the coating portion to the gelling treatment portion.
 45. Theapparatus of forming a film as set forth in claim 44 , furthercomprising: a means for feeding the vapor of the solvent component on atransfer path of the substrate in the auxiliary transfer portion. 46.The apparatus of forming a film as set forth in claim 44 , furthercomprising: a case for covering the coating portion and the gellingtreatment portion, and a means for feeding the vapor of the solventcomponent into the case.
 47. The apparatus of forming a film as setforth in claim 44 , further comprising: a solvent replacement treatmentportion which is disposed adjacent to the gelling treatment portion,dispenses a solvent different from the aforementioned solvent to thesubstrate treated at the gelling portion, and replaces theaforementioned solvent in the film by the different solvent: wherein themain transfer portion transfers the substrate treated at the solventreplacement portion to the heating portion: wherein the auxiliarytransfer portion transfers the substrate treated at the gelling portionto the solvent replacement portion.